Flexible exoskeleton mask with inflating seal member

ABSTRACT

A patient interface, including a mask assembly and a headgear assembly, provides improved facial sealing and improved ease of use. The mask assembly includes an inflating or ballooning seal. The seal can be secured between two portions of a snap-fit exoskeleton. The headgear assembly connects to the mask assembly with flexible straps during course fitting and with more rigid straps following course fitting. The straps include holes that fit over a tapering post on the mask assembly.

CROSS-REFERENCE TO RELATED APPLICATIONS

Any and all applications for which a foreign or domestic priority claimis identified in the Application Data Sheet as filed with the presentapplication are hereby incorporated by reference under 37 CFR 1.57.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to improved patent interfaces,particularly but not solely, for use in delivering artificialrespiration therapy to users or wearers of the patient interfaces, suchas patients. In particular, certain features, aspects of embodiments ofthe present invention relate to mask assemblies of such interfaces andheadgear assemblies used to secure the mask assemblies to a patient.

2. Description of the Related Art

In the art of respiration devices, there are a variety of respiratoryinterfaces that cover the nose and/or mouth of a patient in order toprovide a seal around the nasal and/or oral areas of the face such thatgas may be provided at positive pressure within the interface forconsumption by the patient.

The interfaces must provide an effective seal against the face to reducethe likelihood of significant leakage of the respiratory gas beingsupplied. In many interfaces, a good seal often is attained only withconsiderable discomfort for the patient, with temporary success and/orwith significant time spent fitting the interface to the patient.

With respect to the discomfort for the patient, this problem is mostcrucial in acute care medical environments. In such environments, thepatient will be required to wear the interface continuously for hours orperhaps even days. If significant discomfort is experienced, the patientwill not willingly tolerate the mask for the desired long durations.

In many constructions, even a good seal can be temporary due to aninability to seal effectively when the face of the patient becomesdistorted. For example, when the patient is sleeping on a side, one sideof the headgear may be pulled tight while the other side becomes loose.This asymmetric loading can twist the axis of the interface relative tothe axis of the head due to the net torque from the headgear and anyassociated breathing tube. The twisting of the axis can result inleakage on one side of the interface. In addition, a side-sleepingpatient may also distort the facial contours (e.g., in the nasal area)around the seal, which may lead to further leakage.

Finally, in acute care settings, the speed with which respiratorytreatment can be established is important. Accordingly, with someheadgear configurations, the ability to rapidly establish a satisfactoryseal has been identified as an area in which current configurationscould be improved.

SUMMARY OF THE INVENTION

It has been found that improvements can be made to both sealing of theinterface to the face of the patient and securing the interface to theface of the patient with headgear.

Because the interface may be worn for prolonged periods in a hospitalfor example or when sleeping, comfort preferably should be maximizedwhile also maintaining sufficient pressure on the interface to provideproper location and an adequate seal against the face, thereby reducingthe likelihood of significant leaks. For example, any leakage preferablyis less than about 15 L/min. In a hospital setting, it is also possiblethat a patient will not be conscious while wearing the interface. Addedcomfort can also increase the patient's compliance with treatment andresults in better outcomes generally.

It is preferable that the interface and associated headgear is as easyas possible to put on and take off correctly. In particular, it is alsodesirable for a single headgear design to accommodate a wide range ofpatient head sizes, shapes and hair style types, while still beingsimple to work. This is especially the case in a hospital setting wherestaff are regularly fitting and removing patient interfaces andassociated head gear. Desirably, the interface also accommodates variousfacial shapes and sizes.

From the patient's viewpoint, the interface also should provide certainadvantages where possible. For example, the patient may desire to wearglasses such that clearance above the nasal region can be important. Inaddition, the patient may desire to talk to people and, therefore,advances in the interface that can improve the ability to be heardwithout removing the interface can be important. Furthermore, thepatient generally prefers to not have the interface intrude in asignificant manner into the field of vision. Thus, a lower profileinterface is desirable. Finally, from a comfort standpoint, the patientwould desire an interface and headgear configuration that reduces gasleaks that are directed toward the eyes and that has a reduced smell ofmaterials while also having a lower noise level.

Clinically, the healthcare provider desires that the well-sealinginterface provide generally even interface pressure distribution on theskin to reduce the likelihood of point loading or excessive pressuregradients. Such a feature can reduce the likelihood of irritation to theskin of the patient. In addition, flushing of carbon dioxide to reducethe likelihood of rebreathing of carbon dioxide is desirable.

It is an object of the present invention to provide an improved patientinterface and/or an improved headgear arrangement for securing a patientinterface to a patient or to at least provide the public and medicalprofession a useful choice.

In this specification where reference has been made to patentspecifications, other external documents, or other sources ofinformation, this is generally for the purpose of providing a contextfor discussion. Unless specifically stated otherwise, reference to suchexternal documents is not to be construed as an admission that suchdocuments, or such sources of information, in any jurisdiction, areprior art, or form part of the common general knowledge in the art.

The term “comprising” as used in this specification means “consisting atleast in part of” When interpreting each statement in this specificationthat includes the term “comprising,” features other than that or thoseprefaced by the term may also be present. Related terms such as“comprise” and “comprises” are to be interpreted in the same manner.

Certain embodiments of this invention may also be said broadly toconsist in the parts, elements and features referred to or indicated inthe specification of the application, individually or collectively, andany or all combinations of any two or more said parts, elements orfeatures, and where specific integers are mentioned herein which haveknown equivalents in the art to which this invention relates, such knownequivalents are deemed to be incorporated herein as if individually setforth.

The invention consists in the foregoing and also envisages constructionsof which the following gives examples only.

In one aspect, an interface assembly comprises a mask assembly. The maskassembly comprises an endoskeleton. The endoskeleton comprises a centralportion The central portion is delimited by a groove that defines ashoulder. A seal member overlies at least a portion of the endoskeleton.The seal member comprises an opening. At least part of the centralportion of the endoskeleton is exposed forwardly through the opening inthe seal member. An exoskeleton overlies at least a portion of the sealmember. The exoskeleton comprises a rim that defines an opening. The rimand the shoulder interlock to secure the endoskeleton to the exoskeletonwith the seal member secured between the endoskeleton and theexoskeleton. At least part of the central portion of the endoskeleton isexposed forwardly through the opening in the exoskeleton.

In some embodiments, the central portion of the endoskeleton comprisesan opening, a breathing tube connector being secured to the opening inthe central portion of the endoskeleton. In some embodiments, thecentral portion of the endoskeleton comprises an opening, anantiasphyxiation valve being secured to the opening in the centralportion of the endoskeleton. In some embodiments, the central portion ofthe endoskeleton comprises a first opening and a second opening, abreathing tube connector being secured to the first opening and anantiasphyxiation valve being secured to the second opening. In someembodiments, the seal member comprises a face contacting flange that isconfigured to generally encircle a mouth opening and nasal openings of awearer. In some embodiments, the exoskeleton is configured to enclose atleast a tip of a nose of a wearer. In some embodiments, an upper portionof the mask assembly is generally triangular and a lower portion of themask assembly is generally U-shaped. In some embodiments, the maskassembly has a longer dimension from top to bottom than from side toside. In some embodiments, the mask assembly is more flexible about agenerally vertical center plane than any generally horizontallyextending plane. In some embodiments, the seal member comprises a flangethat borders the opening of the seal member, the flange of the sealmember being positioned within the groove of the endoskeleton and beingsecured within the groove by the interlocking endoskeleton andexoskeleton. In some embodiments, a plurality of mounting members aresecured to the exoskeleton. In some embodiments, at least one of theplurality of mounting members comprises a tapering pin. In someembodiments, the tapering pin extends generally parallel to asubstantially vertical medial plane.

In one aspect, a headgear assembly comprises a semi-rigid frame and afirst set of relatively axially inelastic straps. A first set ofrelatively axially elastic straps is secured to the first set ofrelatively axially inelastic straps. The first set of inelastic strapsand the first set of elastic straps are secured to the frame at a firstlocation. A second set of relatively axially inelastic straps is securedto the frame at a second location that is spaced apart from the firstlocation.

In some embodiments, the headgear assembly can be used with any of themask assemblies disclosed herein. In some embodiments, the first set ofinelastic straps and the first set of elastic straps are pivotallyconnected to the semi-rigid frame. In some embodiments, the second setof inelastic straps are integrally formed of a single component, thesecond set of inelastic straps underlying the semi-rigid frame at thesecond location whereby the second set of inelastic straps would beinterposed between a patient and the semi-rigid frame. In someembodiments, the single component comprises a larger dimension than thesemi-rigid frame such that a tab can be defined by the single componentand such that the single component can cover one or more edges of thesemi-rigid frame. In some embodiments, at least one of the first set ofrelatively inelastic straps and the second set of relatively inelasticstraps comprise mounting openings, the mounting openings beingsurrounded by an embossed portion. In some embodiments, the mountingopenings comprise one or more holes. In some embodiments, the mountingopenings comprise one or more crossing perforations. In someembodiments, the headgear assembly is combined with any of the maskassemblies disclosed herein.

In one aspect, an interface assembly comprises a mask assembly. The maskassembly comprises a seal member. The seal member comprises a facecontacting surface. At least a portion of the face contacting surfacecomprises a roughened surface. The roughened surface having an rms of atleast about 18 microns.

In some embodiments, the roughened surface has an rms of between about18 microns and about 70 microns. In some embodiments, the roughenedsurface has an rms of about 50 microns. In some embodiments, the sealmember comprises a face contacting surface, at least a portion of theface contacting surface comprising a roughened surface, the roughenedsurface having an rms of at least about 18 microns. In some embodiments,the roughened surface has an rms of between about 18 microns and about70 microns. In some embodiments, the roughened surface has an rms ofabout 50 microns. In some embodiments, the interface assembly is usedwith any headgear assembly disclosed herein. In some embodiments, theroughened seal of the interface assembly is combined with any otherfeatures of the other interface assemblies disclosed herein.

In one aspect, an interface assembly comprises a mask body coupled to aseal member. The mask body comprises an outer forwardly facing surfaceand an inner rearwardly facing surface. A passage extends through themask body. An antiasphyxiation valve is positioned within the passage.The antiasphyxiation valve is sandwiched between at least one innermember and at least one outer member.

In some embodiments, the at least one inner member comprises a memberthat is integrally formed with at least a portion of the mask body. Insome embodiments, the at least one inner member comprises a strut thatis a monolithic structure with at least a portion of the mask body. Insome embodiments, the strut is a monolithic structure with at least aportion of an endoskeleton. In some embodiments, the antiasphyxiationvalve is seated to the outer member, the outer member being secured tothe mask body. In some embodiments, the outer member comprises an insertthat is secured to an endoskeleton of the mask body. In someembodiments, the outer member is at least partially received within thepassage. In some embodiments, the outer member is snap fit with the maskbody. In some embodiments, the outer member is snap fit within thepassage. In some embodiments, the outer member is secured to asubstantially rigid portion of the mask body. In some embodiments, theinterface assembly is combined with any other feature of any interfaceassembly disclosed herein. In some embodiments, the interface assemblyis combined with any headgear assembly disclosed herein.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects and advantages of the presentinvention will now be described with reference to the drawings ofseveral preferred embodiments, which embodiments are intended toillustrate and not to limit the invention, and in which figures:

FIG. 1 is a block diagram of a humidified positive airway pressuresystem as might be used in conjunction with the patient interface and/orheadgear that is arranged and configured in accordance with certainfeatures, aspects and advantages of the present invention.

FIG. 2 is a side view of an interface body that is arranged andconfigured in accordance with certain features, aspects and advantagesof the present invention. The illustrated body is shown fitted on a userbut without headgear or a breathing tube attached.

FIG. 3 is a perspective view of the interface body of FIG. 2.

FIG. 4 is a front perspective view of an outside of a seal member of theinterface body of FIG. 2.

FIG. 5 is a rear perspective view of an inside of the seal member of theinterface of body of FIG. 2.

FIG. 6 is a schematic section view of a portion of the seal membershowing a rolling and inflating aspect of the seal member.

FIG. 7 is a graphical depiction of properties relating to rolling of theseal member.

FIG. 8 is a schematic section view of a portion of the seal membershowing an additional rolling and inflating aspect of the seal member.

FIG. 9 is a graphical depiction of properties relating to preloading ofthe seal member.

FIG. 10 is a front perspective view of an outside of a supporting memberof the interface body of FIG. 2.

FIG. 11 is a rear perspective view of the inside of the supportingmember of the interface body of FIG. 2.

FIG. 12 is a graphical depiction of properties relating to theinteraction of a support member flexibility and a seal memberflexibility.

FIG. 13 is a front perspective view of another interface, whichgenerally includes a modification of the interface body of FIG. 2,fitted to a user using headgear that is arranged and configured inaccordance with certain features, aspects and advantages of the presentinvention. The illustrated interface is shown with a breathing tube orsupply conduit attached.

FIG. 14 is a front perspective view of an interface that is arranged andconfigured in accordance with certain features, aspects and advantagesof the present invention with a breathing gases entry port located on alower portion of the interface, which entry port is adapted to bepositioned in a vicinity of a chin of a user.

FIG. 15 is a top view of an interface that is arranged and configured inaccordance with certain features, aspects and advantages of the presentinvention, which interface is shown in one or more bending modes.

FIG. 16 is a front perspective view of another interface that isarranged and configured in accordance with certain features, aspects andadvantages of the present invention. The interface is illustrated withheadgear straps shown on only one side.

FIG. 17 is a front perspective view of an interface that is arranged andconfigured in accordance with certain features, aspects and advantagesof the present invention. The interface is illustrated without headgearstraps.

FIG. 18 is a front view of a portion of an interface similar to that ofFIGS. 16 and 17 with a supporting member that is arranged and configuredin accordance with certain features, aspects and advantages of thepresent invention.

FIG. 19 is a front view of a portion of an interface similar to that ofFIGS. 16 and 17 with a supporting member that is arranged and configuredin accordance with certain features, aspects and advantages of thepresent invention.

FIG. 20 is a front view of a portion of an interface similar to that ofFIGS. 16 and 17 with a supporting member that is arranged and configuredin accordance with certain features, aspects and advantages of thepresent invention.

FIG. 21 is a front perspective view of an interface with a supportmember that is arranged and configured in accordance with certainfeatures, aspects and advantages of the present invention.

FIG. 22 is a front perspective view of an interface, which includes theinterface body of FIG. 2, fitted to a user using headgear that isarranged and configured in accordance with certain features, aspects andadvantages of the present invention. The illustrated interface is shownwith a breathing tube or supply conduit attached.

FIG. 23 is a side view of an interface and headgear that is arranged andconfigured in accordance with certain features, aspects and advantagesof the present invention with a breathing tube or supply conduit that isconnected to the interface with an elbow connector.

FIG. 24 is a rear view of an interface that is arranged and configuredin accordance with certain features, aspects and advantages of thepresent invention. The illustrated interface comprises a plenum spacewith a diffuser port.

FIG. 25 is a rear perspective view of an interface that is arranged andconfigured in accordance with certain features, aspects and advantagesof the present invention. The illustrated interface comprises a cyclonicflow inducing configuration.

FIG. 26 is a side view of an interface and headgear that is arranged andconfigured in accordance with certain features, aspects and advantagesof the present invention.

FIG. 27 is a front perspective view of a further interface, whichgenerally includes a modification of the interface body of FIG. 2,fitted to a user using headgear that is arranged and configured inaccordance with certain features, aspects and advantages of the presentinvention. The illustrated interface is shown with a breathing tube orsupply conduit attached.

FIG. 28 is a side view of an interface and headgear that is arranged andconfigured in accordance with certain features, aspects and advantagesof the present invention. The illustrated headgear includes integratedelastic and inelastic straps.

FIG. 29 is a side view of an interface and headgear that is arranged andconfigured in accordance with certain features, aspects and advantagesof the present invention. The illustrated headgear includes integratedelastics and inelastic straps and a spine.

FIG. 30 is a perspective view of headgear that is arranged andconfigured in accordance with certain features, aspects and advantagesof the present invention.

FIG. 31 is a perspective view of an interface and the headgear of FIG.30 shown being fitted to a user.

FIGS. 32( a)-32(d) illustrate a sequence of steps for fitting aninterface and headgear that is arranged and configured in accordancewith certain features, aspects and advantages of the present invention.

FIGS. 33( a)-33(d) illustrate a sequence of steps for fitting aninterface and headgear that is arranged and configured in accordancewith certain features, aspects and advantages of the present invention.

FIG. 34 illustrates a junction of a connection strap and the first strapportion of FIG. 30 with the first strap portion extending over at leasta portion of the connection strap to provide strain relief andreinforcement.

FIG. 35 is a graphical depiction of a relationship between pressure onskin exerted by an interface and headgear assembly and leak rate fromthe interface.

FIG. 36 is a schematic view of a testing configuration for determining arelationship between pressure and leak rate.

FIG. 37 is a perspective view of an interface assembly, including a maskassembly and a headgear assembly, that is arranged and configured inaccordance with certain features, aspects and advantages of the presentinvention.

FIG. 38 is an enlarged perspective view of the mask assembly of FIG. 37.

FIG. 39 is a front view of the mask assembly of FIG. 37.

FIG. 40 is a rear perspective view of the mask assembly of FIG. 37, withan antiasphyxiation valve and a breathing tube connection shown removedfrom position.

FIG. 41 is an exploded perspective view of the mask assembly as shown inFIG. 40.

FIG. 42 is an exploded side view of the mask assembly as shown in FIG.40.

FIG. 43 is a side view of an endoskeleton used with the mask assembly ofFIG. 37.

FIG. 44 is a front view of the endoskeleton and the exoskeleton of themask assembly of FIG. 37, with the endoskeleton and the exoskeletonpositioned side by side for comparison.

FIG. 45 is a plan view of a frame of the headgear assembly of FIG. 37,wherein the frame is shown flat.

FIG. 46 is a sectioned view showing an angle of incidence of straps ofthe headgear assembly relative to the exoskeleton of FIG. 37.

FIG. 47 is an exploded perspective view of an endoskeleton and antiasphyxiation valve with a cage assembly.

FIG. 48 is an exploded rear perspective view of the assembly of FIG. 47.

FIG. 49 is a top exploded view of the assembly of FIG. 47.

FIG. 50 is a sectioned view of the assembly of FIG. 47.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Overall System

With reference to FIG. 1, a humidified positive airway pressure (PAP)system 100 is shown in which a patient P, or other user, is receivinghumidified and pressurized gases through a patient interface 102. ThePAP system 100 can be continuous, variable or bi-level positive airwaypressure or any other suitable form of respiratory therapy. In someconfigurations, the PAP system 100 could be or include a hospitalventilator or any other suitable form of respiratory therapy. In someapplications, the interface 102 can be used with non-humidified PAPsystems.

The interface 102 connects to a conduit that defines a humidified gasestransportation pathway or inspiratory breathing tube 104, for example.The conduit 104 may contain heating means or a heater wire (not shown)that heats the gases or the walls of the conduit to reduce condensationof humidified gases within the conduit.

The conduit 104 connects to an outlet 106 of a humidification chamber108. The humidification chamber 108 preferably contains a volume ofwater 110. The humidification chamber 108 preferably is formed from aplastics material. In some configurations, the humidification chamberhas a highly heat conductive base (e.g., an aluminum base or the like)that is in direct contact with a heater plate 112 of a humidifier 114.

The humidifier 114 includes a suitable controller 116. The controller116 can be any suitable controller or control means and can be anelectronic controller. The controller 116 may comprise amicroprocessor-based controller that executes computer software commandsstored in associated memory.

The controller 116 receives input from sources such as, for example butwithout limitation, a user input 118 (e.g., dial, button and the like)through which a user of the system 100 can set, for example but withoutlimitation, a value (e.g., a preset value, an entered value or the like)that represents a desired level of humidity and/or temperature of thegases supplied to patient P. The controller may also receive input fromother sources (e.g., temperature and/or flow velocity sensors 120, 122through a connector 124, and a heater plate temperature sensor 126).

In response to a user-set humidity and/or temperature value, which canbe input with the user input 118, and the other inputs, the controller116 determines when or to what level to energize the heater plate 112 toheat the volume of water 110 within the humidification chamber 108. Asthe volume of water 110 within the humidification chamber 108 is heated,water vapor begins to accumulate in the volume of the humidificationchamber 108 above the surface of the water volume 110.

The water vapor passes out of the outlet 106 of the humidificationchamber 108 with a flow of gases (e.g., air) provided from a gasessupply blower 128 or other suitable gases supply means, which flow ofgases enters the humidification chamber 108 through an inlet 130.Exhaled gases from the patient's mouth are passed directly to ambientsurroundings in FIG. 1 or, when the therapy is being delivered by aventilator, the exhaled gases are returned to the ventilator via anexpiratory breathing tube (not shown).

The blower 128 includes a variable pressure regulator, a variablepressure regulating means or a variable speed fan 132 that draws air orother gases through a blower inlet 134. The speed of the variable speedfan 132 is controlled by a controller 136 in response to inputs for thecontroller 136 and a user-set, predetermined or preset value of pressureor fan speed with a user input 138 (e.g., a dial, button or the like).In some configurations, the functions of the controller 136 could beperformed by the controller 116.

The patient interface 102 generally comprises a mask and associatedheadgear. The patient interfaces described below find particular utilityin hospital or other urgent care settings where patients often requireartificial respiratory therapy without delay. In addition, patients insuch settings often receive artificial respiratory therapy for prolongedand often uninterrupted periods of time. Accordingly, the interfaces aredesigned to be rapidly fitted to patients and the interfaces aredesigned to provide increased comfort. Preferably, the interfaces andheadgear assemblies are capable of being initially fitted in less thanabout 25 seconds while achieving a leak rate of less than about 20 L/minwith a set delivery pressure through the interface of about 15 cm H₂O.In addition, as shown in FIG. 35, the interfaces and headgear assembliespreferably achieve a leak rate that is less than about 15 L/min and askin surface pressure that is less than about 22.5 mmHg with a setdelivery pressure through the interface of about 15 cm H₂O. The skinsurface pressure of 22.5 mmHg has been found to be clinicallysignificant in reducing the likelihood of developing pressure sores overprolonged treatment periods. Leakage rates of about 15 L/min have beenfound to be relevant to stability of equipment used to provide thepressurized gases. In some configurations, the skin surface pressure canbe less than about 18 mmHg with a leak rate of less than about 11 L/min.

With reference to FIG. 36, a method of determining skin surface pressureand leak rates will be described. As shown in FIG. 36, one or moresensors 150 can be positioned on the face of the test subject P. Thesensor or sensors 150 can be positioned along a contact region for theinterface 102. Preferably, the sensor or sensors 150 are positionedalong regions that are prone to developing pressure sores duringtreatment (e.g., the region extending from the cheek bones, under theeyes and across the nasal bridge). The sensors 150 are adapted to sensepressure. In some configurations, the sensors 150 are pressuretransducers. Preferably, the sensors 150 are pressure transducers thathave an operating range between about 0 mmHg and about 100 mmHg. Morepreferably, the sensors 150 are pressure transducers that have anoperating range between about 0 mmHg and about 50 mmHg. The sensors 150also preferably are thin film pressure transducers. In someconfigurations, the sensors 150 have a thickness of about 0.5 mm orless.

With the sensors 150 positioned on the face of the test subject, theinterface 102 can be applied to the face of the test subject such thatthe interface rests on the sensors 150. The pressure source 128 can beturned on such that pressurized gases are supplied to the test subjectthrough the interface 102. Preferably, the gases are pressurized toabout 15 cm H₂O for purposes of the analysis. The interface 102 can besecured in place with tension provided by a headgear assembly 700.Preferably, the headgear assembly 700 is used to provide sufficienttension to reduce to about zero the leakage between the interface andthe face of the test subject in the eye region. For purposes of thetest, no bias flow holes are provided (i.e., any bias flow holes in thesystem are occluded) in the system such that any leakage generallyoccurs only between the interface and the test subject.

With the interface tensioned to the face of the test subject and withthe pressure source providing gases at a pressure of about 15 cm H₂O,the test subject then holds their breath such that the pressurized gasesleak from the seal between the interface 102 and the face of the testsubject P. The leakage rate can be determined using a flow meter 152.The flow meter 152 can be integrated with the ventilator or other sourceof positive pressure gases or the flow meter 152 can be a separatecomponent. Preferably, the flow meter 152 is operable in the range ofabout 0 L/min and about 200 L/min.

While the pressurized gases leak, the leakage rate and the pressurebetween the interface and the face of the test subject can be monitored.After the peak leakage rate and the peak pressure have been recorded,the tension provided by the headgear assembly 700 can be adjusted (e.g.,increase) and additional sets of data can be obtained. With multipledata points, a performance envelope can be derived for the interfacethat reflects skin pressure and leakage rates. Multiple test subjectscan be used to provide multiple readings.

Exposed Nose Mask

With reference now to FIG. 2, the illustrated interface 102 comprises aninterface body 200 that generally comprises a compliant seal member 202and a supporting member 204. In FIG. 2, the interface 102 is shown on apatient P without any attached headgear or breathing tube connections.As will be described, at least a portion of an outer appearance of theinterface 102 preferably carries an appearance of a substantialreproduction of at least one human facial feature. In someconfigurations, at least a portion of the outer appearance of theinterface 102 comprises a substantial reproduction of at least a humannose.

As shown in FIG. 2, the illustrated interface 102 is a full face maskthat covers both a nose N and a mouth of the patient P, or other user.The interface 102 can be sized according to the application. In otherwords, the interface 102 can be provided in a variety of sizes toaccommodate use by patients or other users that can vary in age upwardfrom as young as about two years old. The interfaces 102 can be sizedbased upon a measurement from chin to nasal bridge on a patient.Preferably, the size ranges that can be accommodated by each consecutiveinterface size will overlap between about 3 mm to about 7 mm. Morepreferably, the sizes will overlap about 5 mm. For example, threeinterface sizes can be provided based upon a chin to nasal bridgemeasurement criteria: small or size 1 for those with measurements up toabout 110 mm; medium or size 2 for those with measurements from about105 mm to about 130 mm; and large or size 3 for those with measurementsfrom about 125 mm to about 145 mm. Advantageously, the measurementranges overlap from one size to the next such that two sizes can be usedon a single patient within the overlap, which ensures that patients willnot fall into a gap between sizes. Other measurement techniques also canbe used.

An external surface of the interface 102 preferably is of a shapefamiliar to the hand, which improves operation by the person placing theinterface 102 on the patient. Preferably, the shape of the illustratedinterface 102 encourages grasping of the interface 102 during fitting bythe healthcare provider in the chin region of the interface 102. Such agrasping location results in the hand of the healthcare provider notapproaching the eye region of the patient during fitting of theinterface 102, which can be more calming on the patient during fitting.In addition, the protruding reproduction of the nose clearly indicatescorrect placement on the patient and provides a significant visual andtactile cue for correct location, making the mask very easy andintuitive to fit and to use.

Preferably, the interface 102 has a low profile that generally conformsto the contour of the face. This minimizes patient awareness of the maskand minimizes the compressible internal volume, which makes theinterface 102 particularly suitable for use on ventilation. The lowprofile interface 102 preferably is out of the patient's line of sightand only minimally impacts on the patient's peripheral vision. Inaddition, relative to the prior art, the low profile interface 102decreases the compressible volume defined within the interface whilealso decreasing the volume of rebreathable CO₂, each of results in amore desirable interface construction and enhanced interfaceperformance.

Compliant Seal Member

With reference now to FIGS. 2, 4 and 5, the compliant seal member 202 isthe component of the interface 200 that contacts the face of the patientP. The seal member 202 preferably is an inflating or ballooning sealtype. An inflating or ballooning seal type is a type of seal that, whenin use, system pressure or air flow delivered to the interface 102 actsto urge an inwardly extending flange, skirt or other similar member ontoa patient's face to form a substantial seal. Thus, an inflating orballooning seal type is different from seal types that rely solely uponinterface retention forces from headgear to push or deform a cushionagainst the patient's face with enough force to seal the cushion againstthe patient's facial features.

To provide a suitable inflating or ballooning effect, the illustratedseal member 202 comprises a perimetric edge 206 and a sealing flange 208that extends inwardly from the perimetric edge 206. Preferably, thesealing flange 208 extends inwardly from all or substantially all of theperimetric edge 206. As will be described, the perimetric edge 206preferably comprises a rolled edge.

With reference to FIG. 5, the illustrated sealing flange 208 comprisesan extended surface 210, at least a portion of which will abut a skinsurface of a face of a patient P. The extended surface 210, which hasone end portion that is connected to the perimetric edge 206, defines apocket-like structure that captures air or pressure from the air supplyand that urges the flange 208 of the interface body 200 toward the faceof the patient P to a desired degree. The sealing flange 208 can defineat least a part of a sealing portion 212 of the illustrated seal member202. The sealing portion 212 faces the patient, or is closest to thepatient, in use. With reference to FIG. 6, the sealing portion 212 ofthe illustrated seal member 202 can be connected to an enclosing portion214 of the seal member 202 at the perimetric edge 206, which can bedefined by the rolled edge or by a radiused edge.

Preferably, the sealing portion 212 is substantially more flexible thanthe enclosing portion 214. The sealing portion 212 can be formed, forexample but without limitation, of the same material as the enclosingportion 214 but the sealing portion 212 can have a lower thickness thanthe enclosing portion 214. In some embodiments, a different material,such as a silicone, a thermoplastic elastomer or a foam (e.g., open orclosed including a skin) may be used for the sealing portion 212relative to the enclosing portion 214. In use, the sealing portion 212rests against the face of the patient P and, under an internal pressureof the inflating seal and a retention pressure of headgear, the sealingportion 212 is pressed against the face of the patient P to create aneffective seal inward of the perimetric edge 206.

With reference to FIG. 4, the perimetric edge 206 comprises a shape thatcan be defined by a series of radii R₁. The radii R₁ can be defined tothe outer surface of the rolled perimetric edge 206. Thus, the outermostportion of the rolled perimetric edge 206 has a plan view shape that isdefined by the series of radii R₁. In addition, as shown in FIG. 6, therolled over perimetric edge 206 can be defined by a thickness (t) and aninside radius (R₂). FIG. 7 illustrates a desired relationship betweenthe ratio of the inside radius of the rolling portion of the perimetricedge 206 at a particular segment to a wall thickness of the perimetricedge at that particular segment (R₁/t), hereinafter wall ratio, and theratio of the particular radius R₁ of a particular segment of theperimetric edge 206 to the inside radius of the rolling portion of theperimetric edge 206 at that particular segment of the perimetric edge(R₁/R₂), hereinafter roller over ratio. As illustrated, it has beenfound that at a wall ratio of about 4 or less, the perimetric edge 206of the seal member 202 may be subject to collapsing in that particularsegment rather than exhibit a desired rolling. In addition, it has beenfound that a wall ratio of about 7 or more results in a configurationthat may be too stiff in that particular segment to allow a desiredrolling. Moreover, it has been found that at a radius ratio of about 10or more, the particular segment of the seal member 202 may be toostraight to allow a desired rolling. Thus, the region illustrated inFIG. 7 with hatching is a region of desired rollability for theperimetric edge 206. The perimetric edge 206, because it is defined by aseries of radii in plan view, may have various segments that arepositioned within the region of desired rollability. Preferably, atleast the upper portion of the perimetric edge 206 (i.e., the portionthat would leak in the general direction of the eyes when in use) isconfigured such that the dimensions completely fall within the region ofdesired rollability. In other words, preferably those segments satisfythe following two equations: (1) 4≦(R₂/0≦7 and (2) (R₁/R₂)<10. In someconfigurations, at least the nasal portion of the seal member 202 andthe laterally extending portions of the seal member 202 that extendtoward the cheekbones are configured such that the dimensions (i.e.,roll radius, plan radius and wall thickness) result in at least thosesegments falling within the region of desired rollability and satisfythe above-identified equations. In some configurations, at least theportion of the seal member 202 that is located above a generallyhorizontal plane that intersects upper headgear attachment location isconfigured such that the dimensions (i.e., roll radius, plan radius andwall thickness) result in at least those segments falling within theregion of desired rollability and satisfy the above-identifiedequations. In some configurations, the entire perimeter of the sealmember 202 is configured such that the dimensions (i.e., roll radius,plan radius and wall thickness) result in every segmented falling withinthe region of desired rollability and satisfy the above-identifiedequations.

Preferably, the sealing portion 212 curves inwardly to such an extentthat the seal portion 212 forms an acute angle relative to the enclosingportion 214. Moreover, with reference to FIG. 8, the flange 208 is showncontacting a skin surface of the patient P. As shown, relative to apoint of first contact 216, which is the end of the flange 208 disposedfurthest from the perimetric edge 206 in the illustrated arrangement,the start of the radius R₂ can be located at a distance 218 betweenabout 0 mm and about 40 mm or more. As shown in the graph of FIG. 9, arelationship is believed to exist between (1) the distance 218 (i.e.,the distance between the point of first contact 216 and the start of theradius R₂) and (2) a preload angle Θ, which is an angle between theflange 208 and the surface of the skin regardless of the location aroundthe perimetric edge 206. The preload angle can be as shown graphicallyin FIG. 9, which graph was generated empirically. According to thisrelationship, the flange 208 is able to smoothly roll and compressagainst the face of the patient P. As shown in FIG. 9, increasing thecontact length on the skin of the patient P can allow the contact angleto be lower, which indicates that a degree of protrusion of the free endof the flange can be decreased with a significant contact length. On theother hand, a greater protrusion of the free end of the flange canprovide adequate sealing over a shorter contact length. In someconfigurations, the choice of the length 218 can be based upon thevariation of a patient's facial geometry. In other words and by way ofexample only, to achieve a single size mask for varied populations, theflange is longer in the chin region where the dimensions of the facevary the most and the flange is shorter in the nasal region where thegeometry varies less in dimension for a given ethnic group. The nasalbridge dimensions may vary from ethnic group to ethnic group. With thedesired lengths determined, the angle can be determined to reduce thelikelihood of leakage.

As described directly above, the point of first contact 216 resultsbecause the end of the flange 208 protrudes outward in at least somelocations. In some embodiments, the free end of the flange 208 is thefirst surface of the interface body 200 to contact the face of thepatient P. The distance 218 of the flange 208 preferably extends towardthe face of the patient by between about 0 mm and about 10 mm. In someembodiments, the protrusion is between about 3 mm and 7 mm.

Advantageously, because the flange 208 presents toward the face of thepatient, the free end of the flange 208, or another portion of theflange 208, after touching the face of the patient, curves inward (i.e.,is bent inward) from a normal position a progressively increasing amountas the mask is urged into tighter contact with the face of the patient.Thus, the flange is preloaded while being donned, which provides theseal with an enhanced ability to conform around various facial anatomiesand contours, which in turn provides improved sealing performance forthe interface body 200.

Because the illustrated seal member 202 is an inflating or ballooningseal type, the seal member 202 acts to minimize the pressure on theskin. In addition, the seal member 202 acts to distribute pressure andreduce the likelihood of excessive localized pressure distributions. Inother words, the illustrated seal member 202 reduces the likelihood ofpoint-loading or excessive pressure gradients.

With reference again to FIG. 2, the seal member 202 is shown envelopingthe nose N and mouth of the patient P. The seal member 202, as shown inFIGS. 4 and 5, comprises a nasal portion 220 that is shaped to be asubstantial reproduction of the human nose. Preferably, the nasalportion 220 is an upper portion of the seal member 202. In theillustrated configuration, at least an outside surface of the nasalportion 220 is shaped to include a substantial reproduction of a humannose. Preferably, the outside surface and the inside surface of thenasal portion 220 are shaped to include a substantial reproduction of ahuman nose. In particular, in the illustrated configuration, the nasalportion 220 reproduces a substantial portion of a nose shape. Thus, thenasal portion 220 reproduces a majority of a nose shape.

In some embodiments, the nasal portion 220 of the seal member 202reproduces the whole nose or very nearly the whole nose. The nose shapein the illustrated embodiment will be a generalized nose shape ratherthan matched to the particular patient. The illustrated nasal portion220 comprises a nasal bridge 222. The illustrated nasal portion also maycomprise nostril flares 224 or other similar features. Preferably, thenasal portion 220 simulates sufficient features to be representative ofa human nose and to bear semblance to a human nose. In some embodiments,however, the seal member 202 may include a portion shaped to form apocket or nasal chamber 226 that is capable of receiving a human nosebut that does not constitute a substantial reproduction of theappearance of the nose. In other words, the seal member 202 can have anasal portion with a shape that approximates a shape of a rectangularcuboid or that is substantially semi-cylindrical, for example butwithout limitation.

The nasal chamber 226 defined within the nasal portion 220 preferably islarger than a typical nose to accommodate a variety of user's noseswithin the interior of the nasal portion 220. Preferably, the sealmember 202 comprises a septum protrusion 228. The septum protrusion 228extends forward (i.e., away the face when worn) in the region of theseptum to define an enlarged recess on the inside of the seal member 202in the region of the nasal septum of the patient. The seal member 202also preferably comprises an upper lip protrusion 230 that is positionedproximate the center of the upper lip. By providing one or more of theseptum protrusion 228 and the upper lip protrusion 230, the nasalchamber 226 is enlarged at those locations to provide added clearance inthe seal member 202.

With reference to FIG. 5, the sealing portion 212 of the illustratedseal member 202 can be shaped to substantially conform to a shape of atypical face. In the illustrated configuration, the sealing portion 212,which includes the flange 208, comprises a hollow region 232. The hollowregion 232 can accommodate the chin of the patient. The hollow region232 can cup the chin along a portion of the flange 208. With continuedreference to FIG. 5, the illustrated sealing portion 212, which includesthe flange 208, also comprises a valley 234 for the bridge of the nose.The valley 234 can comprise a curved wall that is generally C-shaped orU-shaped.

With continued reference to FIG. 5, the illustrated sealing portion 212,which includes the flange 208, comprises curving cheek portions 236 thatextend between the hollow region 232, which is situated proximate thechin of the patient, and the valley 234, which is situated proximate thebridge of the nose of the patient. The curving cheek portions 236 canconnect proximate the hollow region 232. In addition, the valley 234lies between and, in some configurations, separates and connects thecurving cheek portions 236.

FIG. 4 is a view of the exterior of the seal member 202. The exteriorview better illustrates the enclosing portion 214. In the illustratedconfiguration, the seal member 202 incorporates cheek portions 238, achin portion 240 and the nasal portion 220. The cheek portions 238preferably spread laterally outward from the nasal portion 220. In use,the cheek portions 238 extend outward from the nasal region toward thezygomatic process of the patient. The cheek portions 238 also extenddownward with lateral portions 239 toward the chin portion 240. Thus,the cheek portions 238 extend toward the mandible of the patient at alocation outside of the lateral extremities of the mouth.

With reference again to FIGS. 4 and 5, the seal member 202 defines anaperture 242 that extends from the exterior surface to the interiorsurface of the seal member. The aperture 242 can be positioned at orlower than a location where the mouth of the patient might be positionedduring use of the interface body 200. In some embodiments, the aperture242 is positioned below the nasal chamber 226. The aperture 242 can bedescribed as positioned below the septum protrusion 228. The aperture242 further can be described as positioned below the upper lipprotrusion 230. Moreover, the aperture 242 can be described aspositioned above the hollow region 232 that accommodates the chin of thepatient. Thus, the aperture 242 can be positioned between where themouth of the patient might be expected and the tip of the chin of thepatient. The aperture 242 preferably is positioned along a medial planeof the seal member 202, which medial plane generally bisects the sealmember 202 into a right half and a left half. For reasons that will beexplained below, the illustrated aperture 242 lies on a generally flatplane portion 244 of the seal member.

Supporting Member

With reference again to FIG. 2, the supporting member 204 overlies aportion of the seal member 202. The supporting member 204 issubstantially more rigid than the compliant seal member 202 such thatthe supporting member 204 provides support to the compliant seal member202. However, the supporting member 204 still can be somewhat flexibleand the supporting member 204 preferably is not fully rigid. In someconfigurations, the supporting member 204 has a similar stiffness to anapproximately 1 mm thick sheet of polypropylene or polyethylene plasticmaterial, for example but without limitation.

As shown, the supporting member 204 comprises a perimetric edge 250. Theperimetric edge 250 may have a similar shape to the perimetric edge 206of the seal member 202 but, when a notch 252 is spanned and the spanningdistance is included in the length of the perimetric edge 205, theperimetric edge 250 preferably has a shorter length compared to theperimetric edge 206 of the seal member. In other words, a total lengthof the perimeter of the supporting member 204 preferably is less than atotal length of the perimeter of the seal member 202. Due to theinclusion of the upper portion of the nasal portion 220 in the perimeterof the seal member 202, the total length of the perimeter of thesupporting member (even including the dimensions of the notch 252) isless than a total length of the perimetric edge 206 of the supportingmember 204.

In some configurations, the seal member 202 extends outward beyond thesupporting member 204 in all locations. As illustrated in FIG. 6, theradius R₂ can be defined with a spacing RO of between about 3 mm andabout 6 mm defined from the perimetric edge 250 of the supporting member204 to an outside surface of a rolled over portion of the seal member202.

As shown in FIGS. 10 and 11, the illustrated supporting member 204comprises a contoured plate-like appearance. In other words, thesupporting member 204 has form in three dimensions yet does not have ahigh level of relief. Preferably, the supporting member 204 has a totaldepth of relief of less than about 50 mm and about 65 mm in an interfacesized for an average adult interface.

The otherwise generally smooth and continuous appearance of theperimetric edge 250 is interrupted by an upper notch 252. The notch 252is positioned in the region of the nose of the patient. Thus, in theillustrated embodiment of FIG. 2, the supporting member 204 does notinclude a portion that resembles a human nose. By not comprising thehuman nose portion, the supporting member 204 has an improved bulkflexibility. Instead, the shape of a human nose is defined by the sealmember 202 or some other component of the interface body 200. The notch252 improves the flexibility of the support member 204. Thus, if thereare different cheek bone angles, the support member 204 will flexslightly to better fit the patient.

In the illustrated configuration, the nasal portion 220 of the sealmember 202 protrudes from the upper notch 252 in the support member 204.The shape of the illustrated notch 252 in the support member 204accommodates the shape of the nasal portion 220 the seal member 204. Thenotch 252, by removing a nasal portion of the support member 204,provides the support member 204 with a shape that has minimal curvaturefrom front to back (i.e., the support member 204 has a low profile andsmall depth of relief when formed).

In overall impression, the illustrated configuration provides a fullface interface that resembles the human form while functioning to assistin controlling the ballooning of the seal member 202 by supporting theenclosing portion 214 of the seal member 202. The external appearance ofthe interface in use is of being partially human, thereby improving theemotional response of patients and of people observing the patient usingthe interface. Importantly, this may improve acceptance of the interfaceby patients and thereby improve compliance.

The notch 252 preferably defines a recess that extends inward from theperimetric edge 250 of the supporting member 204. In the illustratedconfiguration, the notch 252 extends inward toward a center of theinterface body 200 or at least a center of the supporting member 204.The notch 252 may include an extended notch portion 251 to accommodatethe septum. Other suitable profiles also can be provided to the notch252 as desired. In some configurations, the notch 252 may be positionedabove a ridge 253 that defines a valley on the inside of the supportmember 204 to further accommodate the central portion of the upper lip.

In the illustrated supporting member 204, the notch 252 is flanked by apair of upward extensions 254 that are separated by the notch 252.Preferably, the upward extensions 254 define an uppermost extent of thesupport member 204. More preferably, the upward extensions 254 define anuppermost portion of the interface body 200 with the exception ofportions of the very flexible seal member 202.

With reference to FIG. 2, the nose N of a patient P is illustrated inbroken lines. The nose N protrudes into the chamber 226 defined by thenasal portion 220 of the seal member 202 while the notch 252 of thesupport member 204 crosses the medial plane at a location below the noseN. The upward extensions 254 of the support member 204 extend upwardlybeyond a base B of the nose. In the illustrated configuration, theupward extensions 254 extend upward beyond a portion of the interfacebody 200 that is designed to accommodate a tip of the nose N of thepatient P.

The lateral side edges of the notch 252 extend alongside lateral marginsof the nose N such that the compliant seal member 202 can extend alongthe cheekbones and such that the support member 204 can reinforce theseal member 202 in the cheekbone region. Support of the interface body200 on the cheekbones of the patient P can significantly improve thecomfort level experienced by the patient P.

The upward extensions 254 also provide a stabilizing function anddefine, at least in part, means for stabilizing the illustrated mask ona central portion of the face of the patient. In particular, the upwardextensions 254 roughly correspond to or overlap with a location of themaxilla bones of the skull.

The support member 204 generally conforms to a typical lower portion ofa human face. As such and with reference to FIGS. 10 and 11, an outersurface 256 of the support member 204 has a generally convex appearancewhile an inner surface 258 of the support member 204 has a generallyconcave appearance. The inner surface 258 of the support member 204generally conforms to an outside surface of the seal member 202. A chinportion 260 of the support member 204 can comprise a hollow concavityalong the inner surface 258 of the support member 204. In addition, eachof a pair of cheek portions 262 comprises a hollow concavity along theinner surface 258 of the support member.

The perimetric edge 250 of the support member 204 generally extendsoutside of the cheek portions 262 to outside of the chin portion 260 andgenerally follows inside a jaw line of the patient. As such, theillustrated perimetric edge 250 of the support member 204 extends to achin of the patient P. Preferably, a lower portion 264 of the supportmember 204 hooks under the chin of the patient P. By hooking under thechin of the patient P, the support member 204 assists the seal member202 in sealing in this region of the face of the patient P. Theillustrated support member 204 defines an expanse of material that backsthe seal member 202 and reinforces the chamber defined by the enclosingportion 214 of the seal member 202. In some configurations, the supportmember 204 defines a reinforcing rim that generally encircles a portionof the seal member 202.

As illustrated in FIGS. 2 and 3, the interface body 200 generallyreproduces the general shape of the lower half of the user's face. Theinterface body 200 can cover the nose at the upper end. In someconfigurations, the interface body 200 is adapted to overlap with atleast a portion of the nasal bone, which is the bone that extends abovethe cartilage of the nose and that is positioned between the eyes. Atleast the seal member 202 can include wings that extend outward towardthe zygomatic bone of the wearer such that the seal member 202 extendsoutwards to follow the cheekbones. The interface body 200 extendsdownward to follow the jaw line to where the lower portion 264 of thesupport member 204 hooks under the chin.

With continued reference to FIGS. 10 and 11, the supporting member 204also comprises a generally centralized opening 266. The opening 266 ispositioned generally below the notch 252. Preferably, the opening 266 ispositioned along the medial plane of the interface body 200, which isthe plane that divides the illustrated interface body 200 intosubstantially symmetrical bilateral left and right halves. In theillustrated configuration, the opening 266 and the notch 252 both arepositioned along the medial plane. The medial plane intersects, andpreferably bisects, the opening 266 and the notch 252.

The opening 266 in the supporting member 204 preferably corresponds inlocation to the aperture 242 that is defined through the seal member202. The aperture 242 is shown more clearly in FIGS. 4 and 5. Theaperture 242 provides a location for a breathing gases inlet and outletto the chamber that is defined on the face side of the seal member 202.By being positioned on the flat plane portion 244, the aperture 242facilitates convenient connection and sealing of a supply breathing tubeto the seal member 202. The support member 204 in the region of theopening 266 also may be configured to support the connection of thesupply breathing tube (e.g., an elbow connector or other configurationof connector).

Bridge Section

With reference to FIG. 13, some embodiments of the supporting member 204may also include a bridge section 300 that extends at least over theseal member 202 in the region of the notch 252. Thus, in someembodiments, the bridge section 300 may be positioned near theperimetric edge 206 of the seal member 202 in the region of the nasalportion 220. The bridge section 300 may provide additional support forthe inflating seal member 202 in this region. The additional support canbe useful in reducing the likelihood of air leaks along the sides of thenose, which air leaks may direct air in the general vicinity of the eyesof the patient.

With reference to FIG. 14, the bridge section 300 in this embodimentextends over the seal member 202 near the perimetric edge 206 of theseal member 202. The bridge section 300 shown in FIG. 14 preferably isbetween about 5 mm and 6 mm wide. The embodiment of FIG. 14 providesincreased flexibility to the support member 204 and the seal member 202,which provides greater conformability to a wearer's facial geometry. Inother words, the supporting member 204 has a lower flexible stiffness,which allows the interface 200 to flex under a retention force providedby headgear straps while the bridge portion 300 provides support for theseal member 202 in or proximate to the nasal portion 220. The bridgeportion helps to reduce the likelihood of deflection of the seal member202 at the bridge of the nose, which deflection can result in air leaksthat are directed toward the general vicinity of the eyes.

With continued reference to FIG. 14, a load 302 applied in a lateraldirection while the opposite side of the mask is held stationary causesflexing of the interface 200 about the medial plane. In the illustratedembodiment, the flexing reduces the overall width of the interface 200.The force 302 is applied at a location near the cheek portion 262 of theinterface 200. Preferably, the force 302, when having a magnitude ofabout 1 N, will result in at least about 4 mm or more preferably atleast about 5 mm of displacement when measured generally parallel to thedirection of the force 302. While headgear generally does not apply theforce 302 in the direction of the arrow, it has been found that thedescribed flexing can be found in the interface 200. It also has beenfound that the flexing can help achieve an improved seal of the sealingmember 202 over a wide range of facial geometries.

Preferably, the flexing or bending is about the medial plane. In someembodiments, it is preferable that the interface 200 is more flexible ordeformable in the cheekbone region of the interface 200 (i.e., in anupper portion) compared to the jawbone region of the interface 200(i.e., a lower portion). Such a difference in flexure zones can beachieved by the notch 252. Thus, the notch 252 can be used to provide aninterface that is more deformable in the cheekbone region where greateranatomical variation may be expected and where the face is moresensitive to discomfort.

With reference now to FIG. 15, the interface 200 is capable of flexingup to approximately 20 degrees under typically encountered forces fromheadgear when in use. For example, FIG. 15 illustrates the interface200, which comprises the seal member 202 and the supporting member 204.The supporting member 204 preferably is sufficiently flexible to deformsubstantially about the medial plane M. The interface 200 that is shownin FIG. 15 from a top down view also is shown in perspective view inFIG. 14 and in side view in FIG. 23. As illustrated, the illustratedinterface 200 comprises a generally triangular appearance from the topdown view of FIG. 15. In addition, a recess 306 is formed along a base308 of the triangle in this view. Of course, the recess 306 isconfigured in accommodate at least a portion of the nose of the patient.In the side view of FIG. 23, the interface 200 comprises a generallysquare or truncated pyramid shape. In some configurations, nosignificant recess can be identified along the interface when viewedfrom the side. The illustrated configuration results in an interfacethat is significantly more flexible about the generally vertical medialplane when compared to the flexibility about a generally horizontallyextending plane. Moreover, the illustrated configuration results in aninterface that is longer from top to bottom than wide from the outermostcheek portion to the outermost cheek portion and that has an upperperimeter surface 310 that is generally triangular (i.e., the upperportion of the perimetric surface that extends between the cheekportions is generally triangular when viewed from the front) and a lowerperimeter surface 312 that is generally triangular (i.e., the lowerportion of the perimetric surface that extends between the cheekportions is generally triangular when view from the front). The upperperimeter surface being generally triangular and the lower perimetersurface being generally triangular along with the nasal portion and thechin portion being recessed relative to the cheek portions provide aconfiguration that is significantly more flexible about the verticalmedial plane when compared to the flexibility about a horizontallyextending plane.

As illustrated in FIG. 15, the left hand side of the interface 200 isbraced to reduce the likelihood of movement and a force 304 is applied.Preferably, the force 304 is applied at approximately the widest pointof the interface 200, which generally corresponds to the cheekboneportions. With the force 304 applied, the interface 200 preferablydeforms such that angle α changes to angle β (i.e., the change in angleis α−β). In one embodiment, the change from α to β is at least about 10degrees when the force 304 is applied at a 3 N magnitude. In a moreparticular embodiment, strap forces typical of an interface in use arebelieved to be capable of causing a deformation of approximately α−β=10°to 50°. In a further embodiment, α−β is at least approximately 10° to30° under typical strap forces of about 1.5 N to about 15 N per strapassuming four straps are used.

In one embodiment, the force 304 with a 1 N magnitude is capable ofdeforming the interface 200 at least about 5 mm. In a furtherembodiment, the force 304 with a 3 N magnitude is capable of deformingthe interface 200 between about 5 mm and about 50 mm. In another furtherembodiment, the force 304 of 3 N magnitude is capable of deforming theinterface 200 between about 15 mm and about 25 mm.

In use, the deflection of the supporting member 204 may occur to closeor open the shape of the interface. In some embodiments, the forceapplied to open the interface 200 a given amount may be less than theforce applied to close the interface 200 by the same amount. Forexample, in one embodiment, a force applied in a direction opposite offorce 304 (i.e., an opening force) of 1 N magnitude is capable ofdeforming the interface 200 at least about 3 mm. In a furtherembodiment, an opening force of 3 N magnitude is capable of deformingthe interface 200 between about 3 mm and about 25 mm. In another furtherembodiment, an opening load of 3 N magnitude is capable of deforming theinterface between about 10 mm and about 20 mm.

With reference to FIG. 12, a flex modulus of the supporting member 204and a flex modulus of the seal member 202 can be interrelated. As shownin the graphical illustration of FIG. 12, the flex modulus of thematerial that forms the seal member 202 preferably is less than about 15MPa. At levels that significantly exceed about 15 MPa, the seal member202 has been found to be too stiff or rigid. On the other hand, the flexmodulus of the support member 204 preferably is less than about 480 MPa.At levels that significantly exceed about 480 MPa, the support member204 has been found to be too stiff or rigid. In addition, the flexmodulus of the support member 204 preferably is above about 50 MPa. Atlevels significantly less than about 50 MPa, the support member 204exhibits excessive flexure. Finally, in defining flexure characteristicsthat are desired in both the support member 204 and the seal member 202,it has been found that a desired interrelationship can be found withinthe hatched envelop shown in FIG. 12.

Flexible Interface Support

Historically, an ability of an interface to seal on a face of a patienthas been hindered by difficulties in conforming to the facial geometryof the patient. The result of the inability to accurately conform theinterface to the particular facial geometry of the patient is excessiveleaking between the interface seal and the patient's face. With priorinterface configurations, tightening of headgear can result in a forcevector on the interface that unevenly loads the seal contact surface onthe face of the patient. Uneven loading of the seal contact surface canresult in pressure points in some locations and in inadequate pressurein other locations. The pressure points may result in irritation of theskin of the patient while the locations of inadequate pressure arelikely to lead to leakage.

With reference to FIGS. 16-21, several embodiments of interfaces 200 areillustrated that present structures that enhance the ability of theinterfaces 200 to conform to and seal with the face of the patient moreevenly. The structures also enhance the ability of the interfaces 200 toconform to a wide variety of face geometries. Preferably, more evendistribution of seal pressure can be achieved by applying a compositeconstruction to the interfaces 200. Thus, the interfaces 200 can flexand contort to accommodate different facial geometries while allowingthe sealing member 202 to inflate or balloon between the support member204 and the face, thereby more evenly distributing the headgear fittingforce onto the interface between the sealing member and the skin.

As shown in FIG. 16, the patient interface 200 comprises the softcompliant seal member 202 and the support member 204, such as thosedescribed above. The seal member 202 is adapted in use to cover a noseand a mouth and to seal around a face along the perimetric edge 206 ofthe seal member 202. For the most part, the interface 200 shown in FIG.16 is the same as the interface 200 shown in and described with respectto FIG. 2. In particular, the features of FIGS. 16-21 described belowcan be implemented with the interfaces 200 that are arranged andconfigured in accordance with the descriptions contained elsewhere inthis application, for example.

An added support member 404 is provided over the seal member 202 or thesupport member 204 in order to provide support to the seal member 202.The support member 404 and the seal member 202 have a small wallthickness and are formed to be complimentary in shape such that the sealmember 202 fits snugly underneath the support member 404. Preferably, inat least one embodiment, the outer profile or shape of the supportmember 404 and the seal member 202 substantially follow the contour of atypical face such that the interface 200 comprises a relatively lowprofile component. In some embodiments, the patient interface 200 may bemore typical in size and dimensions.

The support member 404 comprises a central hub portion 470 that isconnected to the support member 404. In some configurations, the centralhub portion 470 can be directly connected to the seal member 202.Radiating outwards from the hub portion 470 are a plurality ofdisplaceable members 472 or ‘fingers’ that are separated at the ends byspaces 490. The displaceable members 472 preferably are cantileveredfrom the hub portion 470 and extend outwards towards the perimetric edge206. The displaceable members 472 preferably are not rigidly bonded orattached to the underlying seal member 202 so that relative slidingmotion can occur between the seal member 202, or the support member 204when present, and the displaceable members 472.

In some embodiments, the displaceable members 472 may be resilientlyhinged rather than cantilevered. In such a configuration, thedisplaceable members 472 are moveable with respect to one anothersubstantially in a front to back direction (with respect to a face whenwearing the interface 200) such that a force applied by headgear actingon the hub portion 470 urges the interface 200 towards the face.

Preferably, the displaceable members 472 are made of a material that issignificantly stiffer than the soft compliant seal member 202. Forexample, any typical polymer materials used in interface frames may beappropriate, such as polypropylene, polyethylene or polycarbonate, forexample but without limitation. According to one variation, thedisplaceable members 472 may include elastic material extending betweenadjacent lateral margins of adjacent fingers 472 in a manner similar toa catcher's mitt. In other words, webbing of an elastic material mayextend between adjacent fingers 472.

The plurality of displaceable members 472 function to distribute a loadapplied to the central hub 470 across the wider surface area of theinterface 200 thereby providing a more localized force to press theperimetric edge 206 of the seal member 202 onto a user's face. Inparticular, because the displaceable fingers 472 are cantilevered fromthe hub 470 and because the displaceable fingers 472 provide significantfront to back movement at the free ends, the support member 404, whichincludes the displaceable members 472, can conform to a face and canproviding an adequate seal for a wide variation of facial geometries.The sliding movement of at least free ends 474 of the displaceablemembers 470 with respect to the underlying seal member 202 provides amechanism by which the members 472 can put pressure on slightlydifferent parts of the underlying seal member 202 depending upon thediffering geometry of a user's face. Such a construction can increasethe conformability of a given seal to a wide range of facial geometries.

If a wearer has a relatively flat face, it is easier to achieve a goodseal. However, if a user has a face that includes large front to backvariations in shape, the free ends 474 of the displaceable members 472provide localized pressing forces at locations distant from therelatively central hub 470 such that the forces from the headgear can betransmitted from the hub 470 to the free ends 474.

In some configurations, multiple hub portions 470 may be locatednon-centrally on the interface with each hub portion 470 havingdisplaceable members 472 extending therefrom. For example, the chin andleft and right cheeks are preferable places to load a user's face andthe interface may include hub portions 470 at one or more of theselocations.

With reference now to FIG. 18, a further support member 480 can beapplied to the support member 404 shown in FIGS. 16 and 17. In someconfigurations, the support member 480 can be secured to the supportmember 404 to form a laminate-type structure. The support member 480 cancomprise a plurality of displaceable members 482 that are moveable withrespect to each other and/or at least an inner hub portion 484 of thefurther support member 480. Preferably, the fingers 482 of the furthersupport member 480 bear on the fingers 472 of the support member 404.While the illustrated configuration shows the same number ofdisplaceable members on the support member 404 and the additionalsupport member 480, the number and placement of the displaceable memberscan vary. In some embodiments, the plurality of displaceable membersassociated with the further support member 480 may bear directly on theseal member 402.

It will be appreciated that embodiments may be constructed wherecombinations will be present. In other words, some of the plurality offingers (either of the support member or of the further support member)may bear directly on the seal or may bear on other fingers. For examplethe interface 200 illustrated in FIG. 16 includes the support member 204interposed between the seal member 402 and the support member 404(and/or further support member (not shown)). In this embodiment, thefree ends 474 of the support member (and/or further support member) bearon the support member 204, which in turn applies pressure to theunderlying seal member 402. The support member 204 serves to furtherspread the loading forces across the seal member 402 and/or support thesofter seal member 402.

In an alternative embodiment shown in FIG. 19, the free ends 474 of thesupport member (and/or further support member) can bear directly on thecompliant seal member 202 beneath. In the embodiment shown in FIG. 20,the free ends 474 of the fingers bear on the underlying displaceablemembers 482 of the further support member. Any other suitable variationsalso can be used.

The above description gives only a few examples of interface seal typeswhere displaceable members can provide improved facial fit and/orimproved sealing. Other configurations also are possible. The number,spacing and width of the displaceable members can be varied. Inaddition, while the example embodiments illustrated in FIGS. 16-21 allshow support members (and further support members) that are generallycircular in plan view, and/or illustrate displaceable members thatradiate generally from a central location, other shapes are possible.For example, rather than a central generally circular hub, a linear orgenerally rectangular hub may be employed. In such an embodiment, thedisplaceable members 474 may radiate outwards in a ‘leaf like’ structureor like the branches of a tree as shown in FIG. 21, for example butwithout limitation. In such an embodiment, it may be preferable that thehub is substantially aligned with a mid sagittal plane of a user whenwearing the interface. In addition, the hub may include one or more asemi-rigid reinforcing ribs 492 to substantially stiffen the “trunk” ofthe structure. The inclusion of the trunk reinforcing rib 492 provides abeam to resist bending in a given direction.

In a further alternative embodiment the displaceable members may beconstructed having a variable thickness in order to tailor the stiffnessof the cantilevered sections with respect to bending the front to backdirection. For example, the material thickness of the fingers maydecrease towards the free ends. Similarly, the fingers may or may nothave a substantially rectangular plan profile as illustrated in thefigures. For example, the width of the displaceable members may narrowtowards the free ends or may have differing shapes to provide a desiredlevel of displacement.

In a further alternative embodiment, the free ends of the displaceablemembers described in the above embodiments may further include featureswhere the free end bears on the sealing member or on an underlyingfurther support member. For example, a compressible material pad may belocated between the free end and the seal surface such that thecompressible pad bears on the seal member. In another example, the freeend may be rounded at the point of contact between the free end and theseal member. Alternatively, the free end may include a compliant memberthat bears on the seal. The compliant member may be foam or a pluralityof small compressible hoop structures for example.

The forgoing describes example of the interface support that can beapplied in combination with the reproduced nose interface describedearlier. The interface support can be used with other interfaceconfigurations having a soft compliant seal. For example, it is notnecessary to have a support body in between the seal and thedisplaceable support members. In at least one embodiment, thisconfiguration is preferable. In other words, the displaceable supportmembers may act directly on the compliant seal at specific locations topress the interface seal against a users face. Similarly, the interfacesupport is not limited in application to any single head gearconfiguration. The general purpose of the interface support is todistribute the force applied by the headgear to substantially a singlelocation over a wide area and, as such, the disclosed configurations candefine means for distributing a localized force over an interface body.In particular, the interface support can distribute the force over awide area and/or also accommodate a large variation in facial contoursin the front to back direction.

Breathing Tube Connections

With reference now to FIGS. 14 and 22 a breathing tube 500 is shownconnected to the interface 200 in at least two different manners. Theconnections that will be described between the breathing tube and theinterface can be interchanged. In addition, any of the describedconnections can be used with any of the described interfaces.

With reference initially to FIG. 22, the illustrated breathing tube 500is connected to a breathing tube connector with an elbow 504. Thebreathing tube connector can be fitted to and sealed with the aperture242 of the seal member 202. Because the breathing tube connector issecured to the aperture 242, the breathing tube connector extendsthrough the opening 266 formed in the support member 204.

In some configurations, a snap fit arrangement is provided wherein asemi-rigid section of the connector protrudes through the aperture 242in the seal member 202 from one side of the seal member 202 whileanother semi rigid section of the connector can be snap fit to the firstsemi-rigid member. In some configurations, any other suitable techniquefor bonding may be used to form a boss on the soft compliant seal member202 and the connector can be connected to the boss. The elbow 504 can beconnected to the connector.

In FIG. 22, the interface body 200 is shown with the breathing tube 500is connected to the connector with the elbow 504, which connector may beconnected to the seal member 202 or to seal member 202 and the support204. A swivel 502 allows the elbow 504 to rotate relative to theinterface body 200 so the supply conduit 500 can take up differentorientations with respect to the interface body 200, thereby improvinguser comfort during movement, for example but without limitation. Afurther swivel 506 may be provided between the elbow 504 and thebreathing tube 500.

The interfaces described herein also can be used with a bi-directionalflow ventilator with the conduit 500 being short and being connected toa Y-piece. In addition, with a uni-directional flow system provided, forexample, by a CPAP machine, appropriate ventilation holes may beprovided in the elbow 504 or in a region near the bridge of the nose ofthe seal member 202. Moreover, rather than the swivel 502, a ball-jointtype connection can be provided to allow articulation between thebreathing tube 500 and the interface body 200.

In some configurations, such as that illustrated in FIG. 14, theinterface body 200 may include an anti-asphyxiation valve 520. Theanti-asphyxiation valve 520 may be associated with the interface bodyor, in some embodiments, may be incorporated into the breathing conduitconnection or into the elbow connector, for example but withoutlimitation.

While suitable for use, the connection using the elbow 504 results inthe breathing gases entering the interface body 200 substantiallyhorizontally. Accordingly, the breathing gases are directed straighttowards the patient's mouth. It has been found that this arrangement hasseveral disadvantages. For example, patients may feel uncomfortablehaving breathing gases directed straight at their face or mouth.Additionally, the elbow connector 504 is attached to the front of theinterface body 200 and projects outwardly away from the user's face adistance. The top of the interface body 200 (i.e., the nasal portion 220of the interface body 200), where the seal member 202 interacts with thenose, is a portion that is difficult to seal due to considerableanatomical variations among patients. As a result, the bridge of thenose is a common site for interface leakage. Any torque applied theinterface body 200 may aggravate the sealing problem in this region. Inorder to compensate for this effect, it is common to overtighten theheadgear to push the interface body 200 tightly onto a patient's face.The overtightening can lead to discomfort, which is highly undesirable.

With continued reference to FIG. 14, in this embodiment, connection tothe breathing tube 500 can be made with a short flexible tube 522 thatconnects directly to the breathing tube and that enters the interfacebody 200 in the vicinity of the wear's chin and at an angle (projectingdownwards from a wearer's chin). Thus, the gases enter the interface ina direction that is upwards and towards a patient's mouth and nose. Inother words, the tube 522 extends downwards and away from the patient.

The flexible tube 522 connects to the interface body through a port 525.The port 525 is located below a line extending directly outwards througha patient's mouth when facing forward in a normal position. Preferably,the conduit 522 enters the interface body 200 through the port 525 at anangle between about 0° and about 70° from vertical. In someconfigurations, the entry angle is between about 50° and about 60°.Preferably, the entry angle is about 55°.

Preferably the gases port 525 is located in the vicinity of thepatient's chin (i.e., between the patient's lower lip and the tip of thechin,). This port location advantageously positions the port 525 suchthat the front of the interface body 200 has more room for attachmentmechanisms, such as holes, posts, loops, clips and the like. Inaddition, this port location also provides more room for theanti-asphyxiation valve 520 to be located forward of the mouth.Moreover, the location of the breathing gases entry port 525 in thevicinity of the lowest point of the interface interior when in useprovides an effective vomit drain.

The short length of tubing 522 allows natural head movement of thepatient by being very flexible and making the location of the connectionbetween the patient interface 200 and breathing tube 500 distant fromthe interface itself. The connection between patient interface 200 andbreathing tube 500 can be achieved via rigid connectors of a known type.Positioning these connectors away from the chin and neck of a patientimproves the patient's head mobility, especially when tilting the headforwards.

Any other suitable technique of supplying pressurized gases to theinterface body also can be used.

Interface Flow Control

With reference now to FIGS. 24 and 25, diffusion and control of flowwithin the interface body 200 will be described. The interface body 200can be configured in any suitable manner and, in the illustratedconfiguration, the interface body 200 comprises a cavity 600 definedwithin the interface 200 by the seal member 202, for example but withoutlimitation. The seal member 202 can be configured in any suitablemanner, including but not limited to those disclosed within thisapplication. In use, the seal member 202 contacts and seals against theface of the patient. When sealed against the face, the seal member 202reduces the likelihood of air or gases leaking out of the cavity 600.

The breathing tube or another short flexible tube 104 connects to theinterface body 200 in any suitable manner, including but not limited tothose described within this application. The breathing tube 104 suppliesbreathing gases to an entry port 602. The entry port 602 preferably islocated in a region of the interface body 200 that will be locatedwithin the vicinity of the chin of the patient. More preferably, theentry port 602 is configured such that the breathing gases areintroduced in an upwardly inclined direction rather than directly towardthe face of the patient.

With reference to FIG. 24, the cavity 600 defined within the seal member202 can be segmented by a partition wall 604. The partition wall 604 canbe formed within the cavity 600 in any suitable manner. The partitionwall 604 preferably is mounted or supported within the cavity 600 by aboss 606 or other suitable mounting structure. In such a configuration,the partition wall 604 is mounted at a location contained within aboundary defined by a peripheral edge 608 of the partition wall 604. Inthe illustrated configuration, the entire peripheral edge 608 is spacedfrom the inner wall of the seal member 202 or other interface walldefining the cavity 600.

The partition wall 604 can be offset from the inner wall such that a gapis defined between the partition wall 604 and the inner wall. Thepartition wall 604 preferably approximately follows the general shape ofthe cavity 600 such that a plenum space is defined by an approximatelyconstant gap between the partition wall 604 and the inner wall.Preferably, the gap between the partition wall 604 and the inner surfaceof the cavity 600 is less than about 10 millimeters. More preferably,the gap is between about 3 millimeters and about 6 millimeters. In someconfigurations, an incident angle between the flow from the port 602 andthe partition wall is between about 30° and about 80°. In someconfigurations, the incident angle is between about 50° and 70°.Preferably, the incident angle is about 60°.

A diffuser port or a diffuser outlet 610 can be defined by a spacebetween the peripheral edge 608 of the partition wall 604 and the innerwall. In some configurations, the partition wall is generally circularand has a diameter of between about 30 mm and about 100 mm. Inconfigurations, the diameter is between about 40 mm and 80 mm. Theperipheral edge 608 of the partition wall preferably is sized andpositioned to extend near to the outer perimeter of the seal member 202.More preferably, the peripheral edge 608 of the partition wall 604extends into a region that is overlapped by the extended surface 210defined by the flange 208.

The partition wall 604 also preferably is contained within the lowerportion of the cavity 600. More preferably, an upper margin 612 of thepartition wall 604 is positioned at or below the cheekbone level of theinterface body 200. Even more preferably, the upper margin 612 of thepartition wall 604 is generally aligned with a lowermost portion of thenotch 252 for the nasal portion 220. Accordingly, the upper margin 612can be positioned generally at the same position as the nose of thepatient.

In the illustrated embodiment, the diffuser outlet 610 is substantiallyor completely contiguous about the entire partition wall 604. In someconfigurations, the diffuser outlet 610 can be defined solely along theupper margin 612 of the partition wall 604. In some configurations, thediffuser outlet 610 includes the region along the upper margin 612 suchthat the diffuser outlet 610 includes an upper diffuser port portionthat causes breathing gases to flow substantially tangentially over thewearer's cheek bone region.

In some configurations, however, the partition wall 604 does not followthe contour of the inner surface of the seal member 202 and, therefore,the gap defined between the partition wall 604 and the inner surface ofthe seal member 202 is not substantially constant.

The entry port 602 provides gases from the breathing tube into theplenum space that is defined within the cavity 600. The entry port 602leads into the plenum chamber that is defined between the partition wall604 and the inner surface of seal member 202 or, where the seal member202 is replaced by the support member 204 in a particular region of theinterface body 200, the inner surface of the support member 204. Thus,the gases provided through the entry port 602 generally are preventedfrom flowing directly to a patient's mouth by the partition wall 604.Rather, the gases stream impacts the partition wall 604 and is deflectedthroughout the thin plenum chamber.

Where the inner wall that defines the cavity 600 and the partition wall604 approximate the contours of the wearers face, the resulting diffusedbreathing gases flow is substantially tangential to the facial surface.The diffused breathing gases flow exits the plenum chamber through thediffuser port 610, which is defined by the gap between the inner cavitywall and the periphery 608 of the partition wall 604.

The plenum chamber functions as a means to evenly distribute breathinggases flow to the patient around the edges of the partition wall withoutsubstantially increasing resistance to flow. In interfaces thatincorporate an inflating or ballooning seal, the diffuser port 610 thatdirects the flow radially outward from the entry port 602 instead ofhaving the flow continue along the axis of the entry port 602 directsthe flow toward and preferably onto the perimeter of the seal member202, which helps seal the flange 208 to the face of the patient.

In some configurations, the partition wall 604 can be supported in anumber of different locations (e.g., at least two or more locations).The partition wall 604 could be supported in such a manner that thediffuser port 610 includes distinct regions along the peripheral edge608 of the partition wall 604 and/or along the upper margin 612 that arenot a continuous open port. In other words, the diffuser port 610 maynot be a continuous opening extending substantially around the entireperimeter 608 of the partition wall 604.

Preferably, the total cross sectional area of the diffuser port(s) 610is greater than the cross sectional area of breathing gases entry port602. With such a construction, the gases velocity decreases from theentry port 602 to the diffuser port 610. Preferably, the cross sectionalarea of the diffuser port 610 is at least twice the cross sectional areaof the entry port 602. Even more preferably, the cross sectional area ofthe diffuser port 610 is between 2 and 5 times the cross sectional areaof the entry port 602. The enlarging of the cross sectional area reducesthe occurrence of ventilation synchrony issues and jetting effects onthe patients. For example, the spreading and/or slowing of the gasesflow, together with the tangential redirection of the gases flow overthe wearer's skin, results in a more comfortable patient experience.

In some configurations, the partition wall 604 may comprise one or moresmall holes. The holes enable some gentle breathing gases to flowdirectly towards the mouth. Further, in some configurations, the plenumchamber may include flow directing features, such as partitions or thelike, to aid concentration of the flow to particular areas of the face.For example, flow can be directed away from patient receptor area thatwould normally contribute to a hot and uncomfortable feeling duringtherapy. In addition, in some configurations, flow can be directedtoward patient receptor areas that encourage feelings of flow over theface, which can mitigate a feeling of breathlessness or lack of airflow.In some applications, the flow can be diverted away from the nose usinga flow directing feature. The flow directing features may be associatedwith the inner surface of the cavity and/or partition wall 904.

Preferably, the interface body 200 also comprises the anti-asphyxiationvalve 520. The valve 520 may be incorporated into the partition wallsupporting boss 606 in some configurations. In addition, in someconfigurations, the partition wall 604 can be made to flex, move orpivot such that incoming flow is dispersed by the partition wall 604while exhalation can be channeled directly toward the port.

In some embodiments, the interface body 200 may be provided with one ormore pressure monitoring ports (not shown) that is located on theexterior surface of the interface body 200. The pressure monitoringports could extend through the plenum chamber and open into the gasescavity 600. In other words, the opening of the port preferably ispositioned within the gases cavity 600 at a location outside of theplenum chamber defined between the partition wall 604 and the innersurface of the cavity. More preferably, the opening of the port ispositioned along the partition wall 604 on the opposite side of thepartition wall 604 from the plenum chamber. Placement of the pressuremonitoring port behind the baffle wall or partition wall 604, yet infront of the face of the patient, can improve pressure monitoringaccuracy. Such a placement also improves breath triggering or the likewhen used with a ventilator.

The partition wall 604 has been found to provide markedly improvedacoustics in association with patient speech. It has been found that theplenum chamber defined by the offset partition wall 604 improves theinterface acoustics, which enables a patient to be more easily heardwhen speaking. In addition, by diffusing the flow into the interface,the patient does not need to overcome jetting into the nose and/or mouthin order to speak. In other words, the patient does not need to overcomean incoming breath from a ventilator in order to speak.

Furthermore, due to the diffusion of the airflow, the plenum chamberarrangement provided by the partition wall 604 may help reducecondensate formation within the cavity 600. In addition, thearrangements for diffusing flow that are disclosed within thisapplication have been found to reduce the likelihood of a collection ofunwanted water vapor, water droplets and mobile water collecting uponthe interface surfaces. With the diffused airflow, the condensed wateror liquid can be directed flushed from the cavity 600 and directedtoward the port or other collection or drainage location.

With reference now to FIG. 25, a further flow diffusing configuration isillustrated therein. In this configuration, breathing gases entering theinterface body 200 are swirled around the cavity 600 to produce acyclonic motion that preferably is substantially tangential to thesurface of the face of the patient.

The interface body 200 comprises the gases cavity 600. The seal member202 is configured to contact the face and to substantially seal thecavity 600 against the face. The breathing gases entry port 602 islocated in the vicinity of the chin. The breathing tube delivers gasesto the breathing gases entry port 602 as described elsewhere within thisapplication.

The breathing gases entry port can be positioned within a gases swirlingstructure 620. The swirling structure 620 comprises substantiallycylindrical wall 622 extending substantially perpendicular to theinterface cavity wall. In other words, with a patient upright, thecylindrical wall 622 projects forward in a location substantially infront of the mouth of the patient. A substantially conical wall 624extends coaxially with the cylindrical wall 622 and a swirling space 626is defined between the cylindrical wall 622 and the conical wall 624.The conical wall 624 is angled such that the gap between the conicalwall 624 and the cylindrical wall 622 is larger closer to the wearer ofthe interface.

In use, breathing gases enter the swirling space 626 through the port602 in the conical wall 624. The port 602 is offset from the axis of thewalls 622, 624 such that gas flow enters the swirling space 626 offsetand approximately tangentially as shown. As a result, gases flow aroundthe illustrated annular swirling space 626 in an anti-clockwisedirection setting up a rotating flow. The inclined conical wall 624urges the rotating flow towards the patient (i.e., in a direction out ofthe page in FIG. 25). As the flow rotates and moves towards the patient,the gas flow peels off the top of the conical wall 624, which results ina sweeping blade of air moving outwards and towards the patients face.The resulting flow across the wearers face is diffuse and preferablytravelling slower than the gases stream entering the swirling structure.In some configurations, the flow of air toward the face of the patientis less than about 8 m/s. In some configurations, the flow toward theface of the patient is less than about 6.5 m/s In a similar manner tothe plenum chamber embodiment described earlier, the result is improvedcomfort for the patient.

Headgear

The interface body 200 can be secured on the patient using any suitableheadgear assembly 700. Several different headgear assemblies now with bedescribed with reference to the drawings.

Initially, with reference to FIG. 26, it can be seen that the headgearassembly 700 is used to restrain the interface body 200 against movementcreated by the pressurized gas flow being introduced between the patientP and the interface body 200. A force vector R1 results from thegeometry of the interface body 200 and the flow of gases into theinterface body 200. An equilibrant vector E1 can be envisaged extendingin the opposite direction. Ideally, a single strap could be used tosecure the interface body 200 to the face so long as the single strapwas positioned along the line of action of the equilibrant vector E1.Given a desire to capture the chin, a line of retention LR also can beenvisioned. The line of retention LR extends along an uppermost portionof the ears and through a center of area of the interface body 200.

Preferably, the interface body 200 is primarily supported on at leastthree parts of the patient's face: left cheekbone, right cheekbone andchin. Preferably, the strap attachment positions on the interface body200 approximately correspond to the vertical positions of the cheekbones for the upper straps and the chin region for the lower straps.Such a configuration provides a symmetrical force pattern by which theheadgear retains the interface on the patient's face.

While some of the headgear assemblies 700 that will be described cancomprise a single strap that extends generally along the line ofretention LR, other headgear assemblies 700 will comprise two or morestraps (e.g., FIGS. 13, 16, 22, 23, 26 and 27). For example, in theconfiguration of FIG. 16, the headgear assembly 700 comprises a strapthat extends in two directions from the interface body 200 in order tosecure the interface body 200 to a user's face. While the strap is shownon only one side for convenience, a similar strap would be used on theother side of the interface body or the same strap could extend to bothsides of the interface body 200.

With reference now to FIGS. 13, 22 and 27, further examples of headgearassemblies 700 are shown that can be used to mount the interface body200 on the patient. These headgear assemblies 700 are provided forillustration and other headgear types may be equally suitable.

Slots and Hook and Loop Fasteners

In the example of FIG. 22, the headgear assembly 700 comprises includesan upper strap 702 and a lower strap 704. The upper strap 702 extendsaround the back of the head of the patient above the ear. The lowerstrap 704 extends around the back of the neck of the patient below theear.

Each strap 702, 704 is secured to the supporting member 204 of theinterface body 200. The straps 702, 704 may be secured to the supportingmember 204 by passing through clips. However, in some configurations,the straps 702, 704 may be secured to the supporting member 204 withslots 706 that can be formed through the supporting member 204. Inparticular, free ends 708 of the straps 702, 704 can pass through theslots 706. The free ends 708 of the straps 702, 704 can be secured, forexample but without limitation, by hook and loop fasteners such asVelcro® or the like, back onto the remainder of the strap. Othersuitable termination techniques also can be used.

In some configurations, the upper strap 702 can be secured to thesupporting member 204 at a lower region while the lower strap 704 can besecured to the supporting member 204 at an upper region. In suchconfigurations, the straps 702, 704 cross over at the side of the headof the patient.

Interface Body with Integrated Strap Portions

With reference to FIG. 13, the illustrated supporting member 204comprises integral extended strap portions such as upper extended strapportions 710 and lower extended strap portions 712. Each extended strapportion 710, 712 may terminate in an arrangement for securing a strap(e.g., the upper strap 702 and the lower strap 704). Such an arrangementcan be provided in the form of a slot 714. Other arrangements are alsopossible. For example, the ends of the upper and lower headgear straps702, 704 and the ends of the integral strap portions 710, 712 may beprovided with suitable complementary connectors, buckles and holes, orthe like.

Single Point Adjustment

FIG. 27 illustrates a further configuration for headgear assemblies 700in which the headgear assembly 700 can be more easily adjusted.Adjustment for desired positioning and/or tensioning of the interfacebody 200 is desired. Current approaches to provide adjustability use acombination of adjustable mechanisms, such as the hook and loop endsdescribed with respect to FIGS. 22 and 13, for example but withoutlimitation. The combination of adjustable mechanisms are connected totwo, three, four or more discrete anchoring points on the interface body202. Each connection to each anchoring point needs to be adjusted in aseparate process, which makes achieving generally symmetricalpositioning and loading of the interface body 200 a challenge.

With reference to FIG. 27, the illustrated headgear assembly 700 andadjustment system incorporates at least one sliding connection betweenthe headgear assembly 700 and the interface body 200. Preferably, the atleast one sliding connection comprises an upper sliding connectionbetween the upper strap 702 and an upper portion of the interface body200 and a lower sliding connection between the lower strap 704 and alower portion of the interface body 200.

The sliding connections may comprise a line 716 passing across the outersurface of the interface body 200. The line 716 connects to the headgearstraps 702, 704 on each side of the interface body 200. The line 716 canbe slidably secured within sliding clips 718 on the exterior of thesupporting member 204. Preferably, the chosen materials for the line 716and the clips 718 allow a low friction contact to enable easy relativemovement or sliding of the line 716 relative to the clips 718. In someconfigurations, the line 716 can be completely or partially enclosedwithin a lumen of a hose or tube to protect the sliding mechanism and/orto reduce the likelihood of objects (e.g., hair) becoming caught in theadjustment mechanism.

The clips 718 preferably capture the line 716 to reduce the likelihoodof the line 716 separating from the clips 718 or the interface body 200.The captured but slidable line 716 enables the headgear and theinterface body 200 to remain connected when the interface body 200 isremoved from the head or face, for example. Preferably, the clips 718allow removal of the interface body 200 from the line 716 if desiredwhile the line 716 remains attached otherwise and during normal useconditions.

The clips 718 preferably are positioned to guide the line 716 across theinterface body 200 at a location below the level of the nasal portion220. The clips 718 also may be used to provide a sliding interfacebetween the ends of the lower strap 704. The lower clips 718 guide theline 716 across a lower portion of the interface body 200.

In some configurations, the clips 718 may comprise one or more rotatingpulley wheels to further reduce friction and allow enhanced slidability(i.e., relative movement between the line 716 and the interface body200). In this respect, the term “sliding” has been used to broadlydescribe the relative motion between the line 716 and interface body200. Low friction in the circuit of the line 716 allows the line 716 tobe kept in tension all around the circuit of a loop defined by the line716 as the interface body 200 and/or the headgear assembly 700 moves onthe face or head during use, for example but without limitation.

With reference to FIG. 27, the single adjustment line 716 passes throughthe sliding connections 718 to the interface body 200 and throughsliding connections 720 on the right and left side portions of theheadgear assembly 700. The two end portions of the adjusting line 716can come together at a clasp 722. Ends 724 of the adjusting line 716 canbe pulled laterally apart to further pull the adjusting line 716 throughthe clasp 722, which reduces the length of the loop of the adjustingline 716 and which tightens the fit on the patient (i.e., increases thetension). The clasp 722 can allow the adjusting line 716 to pass throughupon application of sufficient tension. The clasp 722 can have anysuitable form. In some configurations, the clasp 722 can comprise aretractable key ring-type of component, a clamp, a jam cleat, a camcleat, a wheel, or a ski binding type ratchet mechanism or any othersuitable adjustment mechanism.

In some configurations, only one end of the adjustment line 716 isadjustable through the clasp 722. The other end of the adjustment line716 could be fixed or anchored. In some configurations, the other end ofthe adjustment line 716 is fixed to the clasp 722, to the interface body200, the one or more of the straps, or to the interface body 200 alongwith the clasp 722, for example but without limitation.

In some configurations, the clasp 722 may have a predetermined oradjustable limit to how much tension in the loop it can resist. In suchconfigurations, the clasp tension limit can be used to set a limit tohow much force the retention system can exert on a user's face. Theclasp 722 may also be a wheel rotatably fixed to the support member 204with the adjustment line 716 wound on about the wheel such that rotationof the wheel in one direction tightens the loop defined by theadjustment line 716 while rotation of the wheel in the other directionloosens the loop defined by the adjustment line 716. In this embodiment,a ratchet and release mechanism can be incorporated to hold the line 716in place when adjustment to the wheel is not being made (i.e., with therelease mechanism locked).

In some configurations, the interface body 200 and the loop of the line716 may include only a single clip 718 that is positioned along theupper portion of the support member 204. Preferably, the single clip 718is positioned along or fairly close to the medial plane. In someconfigurations, several clips 718 may be distributed along the interfacebody 200 and the line 716 may be routed to extend through only a portionof the several clips 718. In this manner, the shape of the loop definedby the line 716 can be varied. As a result, the angle of the line 716extending towards the headgear strap portions 720 can be controlled andthe loop defined by the line 716 can be routed around the ears or otheranatomical features of the patient to improve comfort and/or fit.

As described, the headgear assembly 700 shown in FIG. 27 and describedabove features a single and simple adjustment for theinterface-to-headgear connection. In other words, a single adjustmentpoint can be effective in reducing and/or increasing the effective sizeof the patient interface to fit users of varying sizes and anatomicalgeometries. In addition, the single point of adjustment is all that isrequired to adjust the tension of the interface. In particular, thesingle point of adjustment in the illustrated configuration allows theinterface and the headgear to remain symmetrically positioned on theface during and after adjustment of the tension in the line 716 whilealso allowing some gliding movement during use and during pressurizationof the inflating seal.

One of the advantages of the interface body 200 and the headgear 700featuring the line 716 is that the adjustments of the interface body 200and/or the headgear assembly 700 can be made when the headgear assembly700 and the interface body 200 is in position on the head and face. Thisgreatly improves the ease of use of the interface body 200 and theheadgear assembly 700 and allows for simplified adjustments to be made,which provides added comfort to the patient. Quick attachment andadjustment of the interface body 200 allows therapy to begin as soon aspossible. Moreover, this adjustment system finds application with manydifferent headgear configurations and many different types of patientinterfaces.

Easy-Fit Headgear

FIG. 26 illustrates a headgear assembly 700 that can be quickly andeasily placed onto a patient and/or adjusted by at least one of thepatient or healthcare provider.

With most interface bodies, but particularly with the interface body 200that comprises an inflating type seal, the headgear assembly 700preferably has only a small amount of stretch. In other words, theheadgear assembly 700, where it connects to the interface body 200,preferably has no stretch or virtually no stretch. However, interfacesthat have the inflating seal can be especially difficult to fit with anappropriate level of tension pulling the interface body 200 onto theface of the patient. For example, if the interface body 200 is fitted tothe patient with no breathing gases flow delivered to the interface body200, the tension applied to keep the interface body 200 comfortably onthe patient's face may not be sufficient to reduce the likelihood ofsubstantial leakage when the breathing gases are delivered.

With reference to FIG. 26, the patient P has the interface body 200positioned over the mouth and nose. The headgear assembly 700 includestwo generally inelastic connecting straps 730 on each side of theinterface body 200 and two generally elastic connecting straps 732 oneach side of the interface body 200. The connecting straps 730, 732connect the interface body to the balance of the headgear assembly 700.

The inelastic connecting straps 730 are fixed to any suitable headgear700, including an encircling headgear 734, at one end and the inelasticconnecting straps 730 preferably are connected to the interface body 200with an adjustment mechanism 736 that allows the length of the inelasticconnecting strap 730 to be varied (i.e., allows adjustment of the lengthof the connection between the interface body 200 and the headgear 734).In some applications, the adjustment mechanism 736 may be located at theend of the inelastic connecting strap 730 that connects to the headgear734 instead of the interface body 200. In any event, the adjustmentmechanism 736 preferably is positioned in a location that allowsmanipulation while the head of the patient is resting on a pillow orother structure such that the adjustment mechanism 736 can bemanipulated without moving the head of the patient P.

The adjustment mechanism 736 may comprise any suitable structure. Insome configurations, the adjustment mechanism 736 comprises a frictionclasp that is fixed to the interface body 200 and through which theinelastic connecting straps 730 extend. The friction clasp can operateby a friction element that is biased to grip the connecting strap 730 toreduce the likelihood of the connecting strap passing through thefriction clasp. When adjustment is required, the friction member can bedisengaged from the connecting strap 730, thereby allowing the straps730 to lengthen as desired. The friction clasp provides a simplemechanism 736 that can be easily operated with one hand. In someconfigurations, the adjustment mechanism 736 can comprise a ladder lock,a buckle, a ratchet, a clamp, a cam cleat or a post and hole engagement,for example but without limitation.

Many different types of adjustment mechanisms 736 can be provided toallow the length of the relatively inelastic connecting straps 730 to beadjusted. For example, while friction clasps and various forms of camcleats may be particularly appropriate for configurations where theconnecting straps 730 are rope, cord or the like, other forms ofadjustment may be more appropriate, especially where the connectingstraps 730 are semi-rigid. For example, a ski binding type ratchetmechanism or other clamp locking mechanism may be used as appropriate.

In some configurations, the adjustment mechanism 736 is of a lockingtype having at least two modes. In the first locking mode, the length ofthe substantially inelastic connecting straps 730 cannot be lengthened.In the unlocked mode, the length of the straps 730 can be adjusted inboth directions (i.e., lengthened and shortened). In someconfigurations, the length of the straps 730 can be shortened when therespective adjustment mechanism 736 is in the locking mode but thelength cannot be lengthened.

In some configurations, the locking mode may be operable to reduce thelikelihood of lengthening and shortening adjustments of the respectivestraps 730. In some configurations, all of the adjustment mechanisms 736are located on the interface body 200. Preferably, all of the adjustmentmechanisms 736 are located on a forward facing surface of the interfacebody 200. Such positioning of the adjustment mechanisms 736 wouldfacilitate length adjustment of the straps 730 while the patient Premains with the back of their head supported on a pillow, for example.

The relatively elastic upper and lower connecting straps 732 can bearranged in parallel with the relatively inelastic connecting straps 730such that both sets of the straps 730, 732 extend between the interfacebody 200 and the headgear 734. In other words, the relatively elasticconnecting strap 732 is fixed to the headgear 734 at one end and also isfixed to the interface body 200 at the other end. The connectionlocations of the relatively elastic straps 732 may substantiallycoincide with the connection locations of relative inelastic straps 730.In some configurations, however, the connection locations may be offsetsuch that the inelastic and elastic straps 730, 732 respectively connectto the headgear 734 and the interface body 200 in differing locations.

The relatively elastic connecting straps 732 preferably are extensile(i.e., stretchable). In some configurations, the length of therelatively elastic straps 732 can be stretched to between approximately1.5 times and approximately 3 times the un-stretched length. Preferably,the length of relatively elastic straps 732 can be stretched toapproximately double the un-stretched or relaxed length. Preferably, therelatively elastic straps 732 are not adjustable in length in any wayother than through stretching of the strap material.

The parallel arrangement of the relatively elastic straps 732 and therelatively inelastic straps 730 facilitates a two-stage fitting process.The relatively elastic straps 732 allow a coarse fitting before a finalfitting is achieved using the relatively inelastic straps. In some acutecare applications, it is desired that respiratory therapy is deliveredto the patient as quickly as possible. In order to achieve quickinitiation of treatment, a preferred fitting procedure begins withholding the interface body 200 to the face of the patient P beforefitting the headgear assembly 700 over the head of the patient P. Insome fitting methods, the fitting procedure occurs substantially in linewith the head of the patient (i.e., substantially aligned with themid-sagittal plane of the patient).

The method of fitting the interface body 200 to the patient P cancomprise: (1) gripping the interface body 200 in one hand and theheadgear assembly 700 in the other hand; (2) positioning the interfacebody 200 over the mouth and nose of the patient in order to delivertherapy as quickly as possible (i.e., the therapeutic airflow hasbegun); (3) pulling the headgear assembly 700 rearward over the head ofthe patient until a desired headgear position is approximated; (4)releasing the interface body 200 and/or the headgear assembly 700 whilethe relatively elastic straps 732 provide sufficient tension force tohold the headgear assembly 700 on the head and the interface body 200 onthe face while the relatively inelastic connections remain loose; and(5) making a final adjustment of the headgear assembly 700 and interfacebody 200 with the relatively inelastic straps 730. During the finaladjustment, the relatively inelastic straps 730 can be tensioned to adesired level by adjusting the length of the relatively inelastic straps730 and securing the desired level/lengths with the adjustmentmechanisms 736.

The parallel arrangement of the relatively elastic connecting straps 732with the relatively inelastic connecting straps 730 allows the headgearassembly 700 to be fitted such that it will stay in place without humanintervention before the final adjustment of the relatively inelasticstraps 730. The relatively elastic straps 732 allow a large degree ofmovement between the interface body 200 and the headgear assembly 700 toenable the headgear assembly 700 to be fitted over the head and the earsof the patient P with considerable ease. The retention force provided bythe relatively elastic straps 732 preferably is sufficient to retain theinterface body 200 on the face of the patient and the headgear assembly700 on the head of the patient during fitting. While it is not necessaryto provide a sufficient tension to result in proper sealing of theinterface body against the face with the relatively elastic straps 732,in some configurations, the elastic retention force provided by therelatively elastic straps 732 can be sufficiently high to enable sealingof the interface body 200 to the face during use. Nevertheless, it ispreferable that the configuration allows a large range of patient headsizes to be accommodated easily.

The relatively inelastic connection straps 730 are provided to reducethe likelihood of stretching of the headgear assembly 700 duringventilation once the straps 730 have been adjusted to a desiredtension/length. Slight stretching of elastic straps can cause thepressure within the mask to drop slightly. The slight pressure drop cangenerate a response from a ventilator such that a pulsing gases supplycan result from the elastic stretching of headgear or a connectionbetween the headgear and the interface. For this reason, a substantiallyinelastic headgear and connection between the headgear and the interfaceare desired. When used with interface bodies that have an inflatingseal, the desired tension/length for the relatively inelastic connectingstraps 730 can be set while gases are flowing to the interface body andwhile the seal member 202 is inflated.

While, in the above embodiment, the connection between the interfacebody 200 and the headgear assembly 700 is provided by both upper andlower straps on both sides of the interface body 200, a single set ofparallel elastic and inelastic straps 732, 730 can be provided or thestraps can be provided only on one side of the interface body 200. Insome configurations, the parallel elastic plus inelastic straparrangement can be provided to only one of the top or bottom strap setson each side while a single strap (either elastic or inelastic) can beprovided for the other. In some configurations, the parallel elastic andinelastic strap arrangement can be provided to only one side of theinterface body while the other is only a single strap (either elastic orinelastic).

In addition, in some configurations, the parallel arrangement of elasticand inelastic straps 732, 730 can be provided with an arrangement havingno upper and lower straps but only a single level strap. In someconfigurations, the top strap may be secured to the interface body at alower region while the lower strap may be secured at an upper region. Insuch a configuration, the straps cross over at the side of the head ofthe patient.

The above-described method of fitting the interface body 200 to thepatient P is illustrative only and may be altered and even be reversed.For example, the headgear assembly 700 may be fitted to the head of thepatient P first and then straps and the interface body 200 may bestretched over the head of the patient P until the interface body 200 isapproximately in position. Finally, the relatively inelastic connectingstraps 730 can be tightened to the appropriate length, usually whilegases flow is being delivered to the interface body.

Thus, in some configurations, the generally inelastic connecting straps703 are adjusted to a longer length that is sufficient to easily fit theinterface body 200 and the headgear assembly 700 over the head of thepatient. The interface body 200 then is grasped in one hand and theheadgear assembly 700 is grasped in the other hand. The headgearassembly 700 is positioned approximately on the head with one hand. Theother hand stretches the relatively elastic straps 732 of the headgearassembly 700 by pulling the interface body 200 away from the headgearassembly 700. With the interface body 200 pulled away from the headgearassembly 700, the interface body 200 is moved down over the face of thepatient to fit over the mouth and nose. Once released, the relativelyelastic straps 732 provide sufficient retention force to hold theinterface body 200 on the face of the patient and to hold the headgearassembly 700 in place on the head of the patient while the relativelyinelastic connection straps 730 remain loose. In order to completeadjustment of the headgear assembly 700 and the interface body 200, therelatively inelastic connecting straps 730 are pulled through theadjustment mechanism 736 until the appropriate length/tension in therelatively inelastic connecting straps 730 is achieved.

With reference to FIG. 28, a further configuration will be described inwhich the relatively inelastic connecting straps 740 are at leastpartially integrated with the relatively elastic connecting straps 742.The illustrated relatively inelastic connecting strap 740 comprises asubstantially non-stretch strap and is fixed to the headgear 734 at oneend. At the other end, the substantially non-stretch connecting strap740 is connected to the interface body 200 via an adjustment mechanism744 that allows the length of the connecting strap 740 to be varied. Inthe illustrated configuration, the elastic connecting straps 742comprise a passage 746 that extends from one end to the other and withinwhich the relatively inelastic connecting strap 740 is disposed. Theadjustment mechanism 744 can comprise friction clasps or any othersuitable adjustment mechanisms, including but not limited to thosediscussed elsewhere within this application. The adjustment mechanismpreferably is mounted to the interface body 200 but can be positionedelsewhere if desired. An advantage of the illustrated embodiment in FIG.28 is that the configuration is compact, visually unobtrusive and lesslikely to tangle the straps.

It is to be understood that this embodiment may include upper and lowerstraps or only one level of strap(s) between the headgear 734 andinterface body 200. The embodiment of FIG. 28 comprises a locking modefor the relatively inelastic connecting straps 740 by the frictionclasps 744 or other suitable adjustment mechanism. When in the unlockingmode, the relatively inelastic connecting straps 740 can be lengthenedor shortened. When in the locking mode, the length of the connectingstraps 740 are fixed or alternatively cannot be lengthened. When fittingthe interface body 200, the connecting straps 740 and the respectiveadjustment mechanisms 744 provide a strain limiting effect, whichreduces the likelihood of the distance between the interface body 200and the headgear 734 increasing, while the more elastic connectingstraps 742 provide a temporary retention force during coarse fitting.

Like previous embodiments, the arrangement illustrated in FIG. 28 may befitted either interface body first or headgear assembly first. Apreferred fitting procedure fits the interface body and the headgearassembly substantially in-line, as described previously, and begins withplacing the interface body over the face of the patient in order toprovide therapy immediately.

In some configurations, the relatively inelastic connecting member 740may be replaced with, or may be supplemented by, as shown by dottedlines in FIG. 29, a substantially noncompressible/non-buckling spinemember 748 that extends through the passage 746. In this embodiment, thespine member 748 provides a connection between the interface body 200and the headgear 734 that generally resists both elongation andcompression or buckling. In such a configuration, the spine member 748preferably is semi-rigid such that it generally resists buckling andcompressive forces, which allows the headgear to maintain an overallshape.

Especially in connection with a semi-rigid headgear assembly, it hasbeen found that the shape holding, or self-supporting nature, can resultin an overall assembly that is intuitive to fit. In particular, wherethe connection and/or headgear members are self-supporting such thatthey maintain a three-dimensional form, the headgear can be fitted inthe correct orientation with very little if any instruction. In aself-supporting arrangement, the tendency of the straps to not tanglealso reduces the time taken to fit the overall assembly.

The semi-rigid nature of the spine 748 allows the connection lengthbetween the interface body 200 and the headgear 734 to be shortened by asimple process. For example, when the spine 748 is used in place of arope or cord, the connection length with the adjustment mechanism 744 inan unlocked position may have a tendency to shorten “automatically” inresponse to the retention force of the elastic connecting strap 742.This feature further aids the simplicity of the procedures used to donand/or doff the system.

Semi-Rigid Headgear

A further headgear embodiment for use with the patient interface 200 nowwill be described with reference to FIGS. 30 to 32. In the illustratedconfiguration, the headgear assembly 700 comprises a semi-rigid headgearassembly 800. It has been found that an advantage of the headgearassembly such as that illustrated in FIG. 30 is that, when not in use,the headgear assembly can maintain a substantially three-dimensionalform. As a result, the fitting of the headgear assembly to the head ofthe patient is intuitive and may be accomplished consistently andaccurately with little instruction or untangling before fitting.

As used herein, the term “semi-rigid” is used to denote that theheadgear assembly is sufficiently stiff such that the assembled headgearassembly can assume a three-dimensional shape with dimensionsapproximating the head of the patient for which the headgear is designedto fit while also being sufficiently flexible to generally conform tothe anatomy of the patient. For example, some of the other components(e.g., straps) of the headgear assembly may also be partially or wholly“semi-rigid” such that the components are capable of holding athree-dimensional form that is substantially ‘self-supporting’. A“semi-rigid” headgear assembly is not intended to mean that each andevery component of the headgear assembly is semi-rigid. For example, thesubstantially three-dimensional form that the self-supporting headgearassembly may assume may relate primarily to the rear and top portions ofthe headgear assembly. In addition, the “semi-rigid” headgear assemblymay include semi-rigid regions that extend forward of the ears and abovethe ears when placed on the head of the patient.

The illustrated headgear assembly 800 generally comprises a first strapportion 802 that is adapted to engage the head of the patient. Theillustrated first strap portion 802 generally comprises threesub-portions or regions: a lower rear region 804; side regions 806; anda top portion 812. In some configurations, at least the first strapportion 802 can be formed with contrasting colors between an insidesurface and an outside surface such that twists in any portion that isso colored can be readily identified.

The lower rear region 804 is adapted to engage with the rear of head ofthe user. Preferably, the lower rear region 804 is adapted to engagewith the head at a location on or below the external occipitalprotuberance. The lower rear region 804 spans the distance around theback of the head and extends to each side of the head. In someconfigurations, the lower rear region 804 comprises a longitudinalcenter that is adapted to be located about 25 degrees below a horizontalplane that extends through the ear canal of the patient.

On either side of the head, the first strap portion 802 extends upwardinto left and right side regions 806. The side regions 806 generallyextend superolaterally (i.e., upwards and outwards). The side regions806 are adapted to extend behind the ears of the patient. Preferably,the side regions 806 also are adapted to extend behind the mastoidprocesses of the patient. Each of the left and right side regions 806 ofthe first strap portion 802 extends into or comprises an arched portion808. The arched portion 808 bends upward and forward. The arched portion808 is adapted to extend over the respective ears of the patient.Preferably, each of the arched portions 808 terminates at a respectivetermination portion 810. The termination portions 810 preferably areadapted to be located forward of the ears of the patient. In someconfigurations, the side regions 806 and the arched portions 808 of thefirst strap portion 802 do not include a soft inner padding portion butmay comprise a single, self-supporting, resilient material that is indirect contact with the head/hair of the patient.

The top portion 812 of the first strap portion 802 connects the archedportions 808 of the side regions 806. The top portion 812 can bepositioned forward of the ears in some configurations. Preferably, thetop portion 812 is positioned generally vertical from the ears. Morepreferably, a longitudinal center of the top portion 812 is adapted tobe spaced about 13 mm rearward of a vertical plane that intersects theear canals. In some configurations, the top portion 812 comprises afirst segment 814 and a second segment 816 with the first segment 814and the second segment 816 combining to form the top portion 812. Thefirst segment 814 extends upward from an apex of the left arched portion808 while the second segment 816 extends upward from an apex of theright arched portion 808. Preferably, the top portion 812 is formed of aself-supporting and resilient material. In some configurations, the topportion 812 does not include any backing, including a soft paddedbacking layer.

The first segment 814 and the second segment 816 can be connected withany suitable connector 818. The connector 818 can comprise an adjustmentmechanism such that the first and second segments 814, 816 areadjustably connected. The adjustment mechanism of the connector 818preferably is substantially flat on its underside to improve comfort.Preferably, the adjustment mechanism can be adjustable to account forsmall size variations such that a range of sizes can be accommodated.For example, the connector 818 may comprise a series of spaced apertureson the first segment 814 and one or more posts projecting upwards andlocated on the second segment 816. In some configurations, the aperturesand posts provide an adjustment pitch of about 20 mm with one, two,three or more possible positions. This type of adjustment mechanismallows the length of the top portion 812 to be simply adjusted bypushing the post through the appropriate aperture.

While, in some configurations, the first and second segments 814, 816are integrally formed (i.e., the top portion 812 is a single strap thatis permanently or semi-permanently connected to the arch portions 808)and, in some configurations, the first and second segments 814, 816 arenon-adjustably connected, the illustrated configuration allowsadjustment for customization of the headgear assembly 800 to thepatient.

With continued reference to FIG. 30, at least the arch portions 808preferably are sufficiently stiff to resist significant deformation ordisplacement. In other words, the arch portions are sufficiently stiffto resist opening of the arch when a load is applied at or about thetermination portions 810 in a forward direction. The applied loadcorresponds to a strap tension force that may be experienced with theinterface body 200 is in use with breathing gases being delivered to thepatient while the headgear assembly 800 is worn by the patient, forexample but without limitation. Preferably, the termination portion 810is configured to be strong enough to carry a load and exhibits bendingbehavior consistent with the following equation: [(t*w³)/12]*TS>2400,where t is thickness of the material, w is the width of the strap and TSis the tensile strength of the material used to form the strap.Preferably, at least the remainder of the first strap portion 802 of theheadgear assembly 800 (e.g., the arch portions 808, the side regions806, the top portion 812 and the lower rear region 804) are configuredto satisfy the following two equations: (1) [(w*t³)/3]*FM<6,250, where tis thickness of the material, w is the width of the strap and FM is theflexibility modulus of the material used to form the strap; and (2)[(w*t³)/12]*TS<24, where t is thickness of the material, w is the widthof the strap and TS is the tensile strength of the material used to formthe strap. In addition, the strap width preferably is at least 25 mm. Insome configurations, the strap width is about 30 mm. In someconfigurations, the strap has a thickness of about 1 mm.

With reference again to FIG. 30, a left lower strap 820 and a rightlower strap 822 each extend from a respective side of the lower rearregion 804. The left lower strap 820 and the right lower strap 822preferably extend forward from the lower rear region 804. Morepreferably, the left and right lower straps 820, 822 are adapted toextend forward at a location below the ears of the patient.

The left and right lower straps 820, 822 may be formed of a semi-rigidmaterial or may be of a conformable material and not semi-rigid. Whereused herein, the semi-rigid materials may include molded plastic orsheet materials that include but are not limited to homogeneous plasticmaterials and bonded non-woven fiber materials. Where the lower straps820, 822 are semi-rigid, it is preferable that they are formedintegrally with at least the lower rear region 804. In someconfigurations, however, the lower straps 820, 822 can be formedseparately and can be permanently, semi-permanently or removably securedto the lower rear region 804. Preferably, the right and left lowerstraps 820, 822 are formed as an integrated component that, in use, willextend around the back of the head and/or neck of the patient. Theintegrated component can be integrally formed with the lower rear region804 or can be formed separate of the lower rear region 804 and securedto the lower rear region in any suitable manner. Forming the right andleft lower straps 820, 822 in a single piece advantageously reduces thatlikelihood that one of the straps 820, 822 separating from the lowerrear region 804 in a failure mode will release the interface body 200from the face of the patient because the integrated straps 820, 822 willstill be secured around the back of the neck or head of the patient evenif the integrated straps 820, 822 become separated from the lower rearregion 804.

A left upper strap 824 and a right upper strap 826 respectively extendfrom the respective termination portions 810. Preferably, the upperstraps 824, 826 extend forward and around the side of the head of thepatient. More preferably, the upper straps 824, 826 are adapted toextend in a region generally below the eye of the patient. The upperstraps 824, 826 connect to the interface body 200.

In some configurations, the upper straps 824, 826 are formed separatelyfrom the first strap portion 802. The upper straps 824, 826 can beconstructed of a semi-rigid material or of a conformable and/orcompliant material. In some embodiments, the upper straps 824, 826 canbe formed in a laminate structure comprising of soft padding (i.e.,padding on the surface facing the head of the patient) and a generallyinelastic portion (i.e., on the opposite side of the padding from thehead of the patient). Such a configuration is shown in FIG. 30. Any ofthe lower straps 820, 822 or the upper straps 824, 826 may comprise alaminate structure such that the strap portion comprises a soft paddingcomponent at least on the inside of the strap that would contact thehead/face of the patient. Preferably, at least the lower straps 820, 822and, in some configurations the upper straps 824, 826 as well, areconfigured to support a maximum load of about 15 N from the holes ofeach strap. While the straps can be configured to support higher loads,supporting a maximum load of about 15 N provides a small sized strapthat is sufficiently strong to counteract forces encountered when themask is pressurized. Thus, the straps preferably are sized to counteractforces that result from pressurizing the interface 200.

As used herein with respect to headgear and straps, “soft” is used todescribe a hand of the material, which means the quality of the materialassessed by the reaction obtained from the sense touch. In addition, asused herein with respect to headgear and straps, “conformable” is usedto describe the ability of the material to conform to the anatomicalfeatures of the patient (e.g., around a facial feature). In particular,a strap including at least an element of “soft” and/or “conformable”material also may be “semi-rigid” and/or axially inelastic.

The attachment of the upper straps 824, 826 to the respectivetermination portions 810 can be in any suitable manner. In someconfigurations, the attachment is made with a joint that will allowrotation of the upper straps 824, 826 about a pivot point 828 as shownfor example in FIG. 31. The pivot point 828 can be located on thetermination portions 810 at a location that is intersected by a planethat is about 33 degrees from vertical. In some configurations, theplane is about 33 degrees forward of a plane defined by the top portion812. In some configurations, however, the upper straps 824, 826 may beotherwise connected to the first strap portion 802. In someconfigurations, the upper straps 824, 826 can be integrally formed withthe arch portions 808 of the first strap portion 802.

With reference to FIG. 34, a junction between the lower straps 820, 822and the lower rear portion 804 can be integrated, such as in theembodiment of FIG. 30. As shown in FIG. 34, the straps and the lowerportion can be configured with a flexing region 836 to provide a degreeof bend along its width (see arrows 850—which illustrate movement withinthe plane of the paper) and to provide a degree of rotation along anaxial length (see arrow 852). These movements help the straps 820, 822to conform to the anatomy of the patient while not significantlyincreasing bending in the thickness direction relative to a constructionnot having the flexing region 836. As illustrated in FIG. 34, theflexing region may include a grooved region, which has portions withmaterial removed such that the flexing region 836 has the appearance ofvertebrae that can bend and twist to improve the conformance of thestraps 820, 822 to the anatomy of the patient while being reinforced bythe first strap portion 802. Furthermore, the straps 820, 822 can reducethe likelihood of the reinforcing digging in to the patient orpresenting a rigid edge to the patient. The reinforcement can beattached to the straps 820, 822 in any suitable manner, including butnot limited to overmolding, welding, gluing, adhering, cohering, or thelike.

In some configurations, such as that illustrated in FIG. 30, theabove-described first strap portion 802 can be formed from a single flatmember that assumes a three-dimensional headgear shape when the firstand second segments 814, 816 of the top portion 812 are joined together.In some configurations, the first strap portion 802 and the lower straps820, 822 are formed from a single flat member. In some configurations,the first strap portion 802, the lower straps 820, 822 and the upperstraps 824, 826 all are formed from a single flat member. In someconfigurations, the first strap portion 802 and the upper straps 824,826 all are formed from a single flat member. In some configurations,the first strap portion 802 is formed from a first single flat memberand the first and second lower straps 820, 822 are formed from a secondsingle flat member. The first and second single flat members can besecured together in any suitable manner. Moreover, in someconfigurations, one or more portions of the headgear assembly (e.g., thefirst strap portion 802) can be molded or otherwise formed as a threedimensional component.

The flat members may be of a self-supporting, resilient, substantiallyinelastic material, such as Santoprene, polyolefin, polypropylene,polyethylene, foamed polyolefin or non-woven polymer material forexample but without limitation. In some configurations, the flat membersare formed from the polyethylene or polypropylene families. The materialcan be a low density polyethylene such as Dowlex 2517, which is a linearlow density polyethylene that has a yield tensile strength of 9.65 MPa,a break tensile strength of 8.96 MPa, and a flexural modulus—2% secantof 234 MPa. The flat member preferably is formed of a material such thatthe headgear assembly 800 is substantially shape sustaining under itsown weight regardless of the orientation of the headgear assembly 800.In some configurations, the straps do not stretch more thanapproximately 6 mm under a 30 N tensile load. In some configurations,the straps do not stretch more than approximately 3 mm under a 30 Ntensile load.

In some configurations, one or more of the straps or flat members couldbe formed from non woven polyolefin (NWP), which is bonded (e.g.overmolded or laminated) with a polyolefin. In such configurations, theovermolded polyolefin material provides the principle shape sustainingproperties. In addition, the softer NWP material is adapted to contactthe skin and provide a desired comfort level. Furthermore, the NWPmaterial may assist in providing the desired load bearing properties,such as the desired tensile load bearing properties. In someconfigurations, the lower straps 820, 822 may comprise a soft material,such as non-woven polymer, for example but without limitation.

The above-described embodiments of the headgear assembly 800 provide alow-profile and comfortable headgear assembly 800 that has very littleor substantially no stretch. For example, the headgear assembly can havea tensile modulus greater than about 10 kPa. More preferably, theheadgear assembly can have a tensile modulus greater than about 20 kPa.With use of at least semi-rigid materials for the first strap portion802 (i.e., the portions that engage the rear and top parts of the head),the assembled headgear is capable of holding a self-supportedthree-dimensional form. This feature, coupled with features describedwithin this application, result in a headgear assembly that is intuitiveto fit with little or no instruction. In particular, the speed offitting has been found to be significantly faster than existing headgeardesigns.

With particular reference to FIG. 30, the illustrated lower straps 820,822 and the illustrated upper straps 824, 826 include a series ofadjustment apertures 830 to provide an adjustable mechanism for fittingthe headgear assembly 800 to various configurations of the interfacebody 200. The interface body 200 preferably comprises posts 832 that areadapted to engage with the apertures 830 of the straps 820, 822, 824,826. During manufacturing, the apertures preferably are formed usinglaser cutting, which cauterizes the material surrounding the aperturessuch that the durability of the apertures can be greatly increased in asimple to manufacture manner. The illustrated style of attachment andadjustment mechanism is effective in practice and provides an intuitivesolution requiring little or no instruction. In particular, the locationof the adjustment/connection to the interface body 200 advantageously ispositioned on the surface of the interface body. Preferably, thelocation of the adjustment/connection to the interface body 200 ispositioned on a laterally extending portion of the support member 204,which is formed on the outside surface of the interface body 200. Such alocation provides easy access and facilitates the fitting/adjustmentwhile the head of the patient is resting on a pillow, for example. Inother words, the adjustment of the straps can take place at locationsforward of the ears and, more preferably, forward of the rearwardmostsurface of the interface. The adjustment also lends itself to correctbalancing of left vs right side strap length adjustments because of thefinite number of positions defined by the apertures 830. The apertures830 provided in the upper and/or lower straps (820, 822, 824, 826) canbe very easily counted or visually matched to encourage symmetricfitting of the headgear. Moreover, because there is no doubling back ofthe strap during tensioning, such as might be found with the use of aslot and hook/loop component of FIG. 22 for example, the force that canbe applied to the straps 820, 822, 824, 826 during fitting issignificantly less. In other words, there is no multiplier effectpossible with the attachment and adjustment mechanism illustrated inFIGS. 30-32.

In addition, the illustrated straps 820, 822, 824, 826 tend to presentforward naturally due to the semi-rigid configurations. In someconfigurations, only a portion of the illustrated straps 820, 822, 824,826 are formed of a semi-rigid construction. The portion can providesufficient lateral or forward presentation to keep the straps from beinghidden or tangled behind the head of the patient. In addition, in someconfigurations, the portion of the lower straps 820, 822 and the portionof the lower rear region 804 that connect are semi-rigid while thedistal ends (i.e., the ends of the straps 820, 822 that connect to theinterface body 200) are substantially more flexible, while remainingrelative inelastic in an axial direction. The forward presenting natureof the straps 820, 822, 824, 826 makes positioning and alignment of theapertures 830 with the attachment posts 832 of the interface body 200intuitive and easy. Where the straps 820, 822, 824, 826 are relativelylong for a given patient, the straps 820, 822, 824, 826 may projectforward significantly beyond the aperture 830 through which the post 832extends. In this situation, it is possible to double the forwardprojecting strap 820, 822, 824, 826 back on itself and pass anadditional aperture 830 over the post 832. The result is a neat and tidyarrangement where the excess strap length is retained on the interfacebody.

In one embodiment, it is preferred that the attachment between the upperstraps 824, 826 and the patient interface 200 is semi-permanent. Afitting process with such an embodiment now will be described withparticular reference to FIGS. 32A to 32D. In FIG. 32A, the healthcareprovider takes the interface body 200 and places it on the face of thepatient in order to deliver respiratory therapy immediately. Whenplacing the interface body 200 onto the face, the interface bodyincludes a sealing flange 208 as described above. The flange 208includes a recess to accommodate, and/or locate on, the chin of thepatient. Thus, when placing the interface body 200 onto the face, thechin is located within the recess and then the rest of the interfacebody 200 is brought into contact with the face. With the interface bodyin place on the face, the healthcare provider grips the headgearassembly 800, which is joined to the interface body by the upper straps824, 826, with the other hand and raises the headgear assembly 800 overthe head of the patient. As shown in FIG. 32B, the healthcare providerpulls the headgear assembly 800 down over the back of the head of thepatient. The lower straps 820, 822 remain somewhat untangled and presentaround the side of the head due to the semi-rigid construction. Inaddition, the interface body 200 is loosely held against the face by theupper straps 824, 826 As shown in FIG. 32C, the healthcare providesconnects the lower straps 820, 822 to the interface assembly by pushingthe posts 832 through the appropriate apertures 830. If desired, theupper straps can be adjusted as shown in FIG. 32D. Final adjustments canbe made to the upper straps 820, 822 and/or the lower straps 824, 826 tocomplete the final fitting. It will be appreciated that the foregoingsteps need not necessarily be taken in the order recited.

With particular reference to FIG. 31, the headgear assembly 800comprises substantially inelastic upper straps 824, 826 that are securedto the headgear assembly 800 at the pivot point 828. At the other end,the substantially inelastic connecting straps 824, 826 can be connectedto the interface body 200 with an adjustment mechanism that allows thelength of the straps 824, 826 to be varied. For example, the length ofconnection between the interface body 200 and the headgear assembly 800can be adjusted by pushing the post 832 of the interface body 200through an appropriate aperture 830 in each of the straps 824, 826. Eachof the left and right side upper straps 824, 826 can comprise astretchable elastic strap 834 that is secured to the headgear assembly800 at one end and to the interface body 200 at other end in anysuitable manner. Preferably, where parallel straps (i.e., elastic andinelastic straps in parallel) are used, the two straps are differentlycolored from each other to provide a contrast in color between theelastic and inelastic straps. The parallel arrangement of the elasticand non-elastic straps 824, 826, 834 facilitates a two-stage fittingprocess similar to that described earlier. A coarse fitting can beachieved with the elastic straps 834 before a final inelastic fitting isachieved using the inelastic straps 824, 826. In some configurations,the lower straps 820, 822 can be constructed in the same manner as justdescribed.

Headgear

FIG. 33 illustrates a further headgear assembly 900. The headgearassembly 900 can be used in conjunction with a wide variety of patientinterfaces, such as those described previously. In particular, theillustrated headgear assembly 900 is particularly suited to theconfigurations of the patient interface 200 described above. Theheadgear assembly 900 has been configured for easily donning anddoffing, even for people with poor dexterity. In addition, theillustrated headgear assembly 900 is particularly easy and comfortableto put on and remove because there are no straps that extend under orbehind the ears of the patient. In headgear assemblies that have strapsthat extend under the ears of the patient, those straps can catch on theears of the patient while being removed or fitted.

The illustrated headgear assembly 900 comprises a top strap 902 thatextends over the top of the head of the patient. The top strap 902preferably lies substantially flat to the curve of the head of thepatient. Preferably, the top strap 902 is adapted to be positioned overthe top of the head of the patient at a location generally behind theears.

The top strap 902 can comprise a side burn portion 904. The side burnportion 904 extends from the generally vertically extending top strap902. Preferably, the side burn portion 904 extends from the top strap902 at a position generally above the ears. The side burn portionextends downward and forward relative to the ears. The side burn portion904 preferably terminates at a location below and in front the ears ofthe patient.

The headgear assembly 900 further comprises a back strap 906. The strap906 can be pivotally connected at a pivot 908 to the top strap 902 at alocation generally above the ears of the patient. The location of thepivot 908 preferably is in the vicinity of the connection between thegenerally vertically extending top strap 902 and the side burn portion904.

The pivot 908 allows the back strap 906 to rotate between two operatingconditions. In a first operating condition, which is shown in FIG. 33A,the back strap 906 is pivoted upwards to disengage from the back of thehead of the patient, which allows for easy removal of the headgearassembly 900. In a second operating condition, which is shown in FIG.33B, the back strap 906 can be rotated downwards such that a lower rearportion of the back strap 906 engages with the rear of the head of thepatient. Preferably, the lower rear portion of the back strap 906 isconfigured to engage the head of the patient at a position on or lowerthan the external occipital protuberance.

The back strap 906 and the top strap 902 can be provided with a lockingmechanism that is operable to lock the back strap 906 in the loweredposition, which is the position substantially as illustrated in FIG.33B. In some configurations, the locking mechanism comprises a detentand a cooperating protrusion, which can be associated with one of thetop strap and the back strap respectively. The detent and the protrusionpreferably are reflected in matched sets that are located on both sidesof the headgear assembly 900.

In some configurations, the top strap 902 can be provided with theprotrusion while the back strap 906 is provided with the cooperatingdetent. As the back strap 906 is lowered into the position illustratedin FIG. 33B, the detent will align with the protrusion and the backstrap 906 will lock into position, which will enable the back strap 906to pull the interface body 200 onto the face of the patient with thestraps.

To release the back strap 906 so that the headgear assembly 900 can bemore easily removed, the protrusion can be spring biased and can bereleased by pushing against the biasing spring until the protrusiondisengages with the detent. Alternatively, the back strap 906 can belifted with sufficient force to overwhelm but not damage the lockingmechanism. A number of other suitable locking mechanisms also can beused with the headgear assembly 900.

The side burn portions 904 of the illustrated headgear assembly 900 canprovide attachment points 916, 918 from which the straps 920, 922 (i.e.,the upper and lower straps respectively) can attach to the interfacebody 200. In some configurations, the headgear assembly 900 can includeonly a single strap between the interface body 200 and the headgearassembly 900 on each side of the side burn portion 904. In someconfigurations, the upper strap 920 can connect with a lower portion ofthe interface body 200 while the lower strap 922 can connect with anupper portion of the interface body 200 in a criss-cross fashion.

In some configurations, one or more of the straps 920, 922 can be formedof a stretchy elastic material. In some configurations, one or more ofthe straps 920, 922 can be formed of a substantially inelastic material.The top strap 902 and the side burn portions 904 can be formed of asemi-rigid, self-supporting material such that the headgear assembly 900can assume a substantially three-dimensional shape and generally doesnot tangle. In addition, the back strap 906 can be formed of asemi-rigid, substantially self-supporting material. In someconfigurations, the material can comprise a laminate structure of bothconformable and semi-rigid portions, for example but without limitation.

At least a portion of the top strap 902 and the side burn portions 904can include padding to improve patient comfort. The back strap 906 alsocan include at least portions of padding to further improve patientcomfort. The padding can take any suitable configuration that providesat least a layer of padding material on the inside of the headgearadjacent the skin and/or hair of the patient. In some configurations,the padding can be a soft layer of foam or other soft material. In someconfigurations, the semi-rigid headgear components can be completely orpartially encapsulated by a soft material or can be overmolded with asoft material, for example but without limitation.

With reference now to FIG. 37, an interface assembly 1010 is illustratedtherein. The illustrated interface assembly 1010 generally comprises amask assembly 1012 and a headgear assembly 1014. While the illustratedassembly 1010 will be described in more detail below, the mask assembly1012 can be configured in any manner described above, the headgearassembly 1014 can be configured in any manner described above and themask assembly 1012 and the headgear assembly 1014 can be joined togetherin any manner described above. Thus, it is possible to mix and matchmask assemblies and headgear assemblies described anywhere within thisdisclosure.

With reference to FIG. 38, the illustrated mask assembly 1012 generallycomprises a mask seal 1020 that is adapted to contact a face of awearer. The mask assembly 1012 also comprises an endoskeleton 1022 andan exoskeleton 1024 that sandwich at least a portion of the mask seal1020. As with the configurations described above, the illustrated maskassembly 1012 is configured to cover both the nose and the mouth of thewearer. Thus, the illustrated mark assembly 1012 is configured toencircle a mouth opening and nasal openings of the wearer. Differentfrom many of the configurations described above, however, is that theillustrated mask preferably encloses a substantial portion of the noseof the wearer.

The illustrated mask assembly 1012 can be sized according to theapplication. Preferably, the mask assembly 1012 is provided in a varietyof sizes to accommodate use by wearers that can vary in age upward fromas young as about two years old. The mask assembly 1012 can be sizedbased upon a measurement from chin to nasal bridge on the wearer.Preferably, size ranges for the mask assembly 1012 can be providedwherein each consecutive mask assembly size will overlap between about 3mm and about 7 mm. More preferably, the size ranges can overlap by about5 mm. For example, three mask assembly size ranges can be based upon thefollowing chin to nasal bridge measurement criteria: (1) small or size 1for those with measurements up to about 110 mm; (2) medium or size 2 forthose with measurements from about 105 mm to about 130 mm; (3) large orsize 3 for those with measurements from about 125 mm to about 145 mm.

With reference to FIG. 39, the mask assembly 1012 preferably isconfigured to be substantially symmetrical about a generally verticalcenter plane V. The illustrated mask assembly 1012 is longer from top tobottom than from a first outermost cheek portion 1030 to a secondoutermost cheek portion 1032. Moreover, the illustrated mask assembly1012 comprises a generally triangular upper portion 1034 (i.e., theupper portion 1034 has a perimetric surface that extends between thecheek portions 1030, 1032 that is generally triangular when viewed fromthe front) and a lower portion 1036 that is generally U-shaped orsomewhat triangular (i.e., the lower portion 1036 has a perimetricsurface that extends between the cheek portions and that is generallyU-shaped or substantially triangular when viewed from the front).

Given the generally triangular ends and the longer dimension from top tobottom, the illustrated mask assembly 1012, as with the mask assembliesdescribed above, is flexible about the medial or center plane V. Inparticular, the illustrated mask assembly 1012 preferably issignificantly more flexible about the vertical center plane V than anygenerally horizontally extending plane. In other words, the length andthe points formed at the upper portion 1034 and the lower portion 1036that are located along the center plane V help facilitate flexure aboutthe center plane V. On the other hand, the substantially parallel sidesthat form the legs of the U-shape reduce the ability of the maskassembly 1012 to flex about a horizontal plane in the lower portion1036.

Mask Seal

The mask seal 1020 preferably comprises an inflating seal that exhibitsa rollover behaviour similar to the seals described above. Withreference now to FIG. 41, the illustrated mask seal 1020 generallycomprises a forwardly disposed outer surface 1040. The outer surfacedefines an opening 1042 that preferably is surrounded by a flange 1044.The illustrated opening 1042 is generally ovular in configuration, withan elongated dimension in the vertical direction. The flange 1044 in theillustrated configuration has an increased thickness.

As shown in FIG. 40, the illustrated mask seal 1020 also comprises arearwardly disposed sealing portion, which includes a face-contactingflange 1050 that extends inwardly from a perimetric edge 1052. Asdescribed above, the mask seal 1020 preferably is an inflating orballooning seal type. The mask seal 1020 can be configured as describedabove.

Preferably, the mask seal 1020 is formed of silicone, a thermoplasticelastomer, or a foam (e.g., open or closed, including a skin). Morepreferably, the mask seal 1020 is formed of silicone or thermoplasticelastomer (TPE).

In forming the mask seal 1020, a core and cavity set is created that isused to manufacture the mask seal 1020. Preferably, at least a portionof the core and cavity set comprise a roughened finish, which willprovide a surface roughness for the mask seal 1020 that in turn willprovide an improved interaction between a face of a wearer and the maskseal 1020. Any suitable technique can be used to form the roughenedfinish. For example, the roughened finish can be formed by acid etching,by spark erosion, or by machine or micromachining, for example butwithout limitations. In some configurations, the roughened finish can beformed by blasting with grit or other suitable material. In someconfigurations, at least a portion of the core and/or cavity componentsused to mold the mask seal 1020 is roughened by blasting with a materialhaving an about 200 micron average diameter. Preferably, at least aportion of the core and/or cavity components used to mold the mask seal1020 is roughened by blasting with a material having an average diameterof greater than about 1 mm. More preferably, at least a portion of thecore and/or cavity components used to mold the mask seal 1020 isroughened by blasting with a material (e.g., stainless steel shots)having an average diameter of about 1.8 mm. The larger average diameterprovides a rougher surface.

Rougher surfaces reduce the coefficient of friction between the maskseal 1020 and the skin of a wearer. The lower coefficient of frictionthat results from the increased surface roughness, and the correspondingsurface texture of the mask seal 1020, is believed to assist in thereduction of skin abrasion, which can cause skin sores over prolongedperiods. As such, the lower coefficient of friction produced by theincreased surface roughness (e.g., a rms roughness of at least about 18microns) has particular utility with flanges such as those found in therolling seal described above with reference to FIGS. 4, 6 and 7, forexample but without limitation. Preferably, at least the portion of themask seal 1020 expected to contact the skin of the user is texturized.In some configurations, the texturized surface of the mask seal 1020 hasa root mean square (rms) of at least about 18 microns. In otherconfigurations, the texturized surface of the mask seal 1020 has a rmsof between about 18 microns and about 70 microns. In one configuration,the texturized surface of the mask seal 1020 has a rms of about 50microns

Exoskeleton

With reference again to FIG. 38, the exoskeleton 1024 of the illustratedmask assembly 1012 generally overlies a large portion of the mask seal1020. In the configuration of FIG. 38, the exoskeleton 1024 overlies atleast a portion of the nose of the wearer. More preferably, theillustrated exoskeleton 1024 is configured to generally encloses atleast the tip of the nose. Even more preferably, the exoskeleton 1024 ofthe illustrated embodiment is configured to enclose the nose up to alocation just below the bridge of the nose.

The exoskeleton 1024 can be formed of any suitable material. Preferably,the exoskeleton 1024 is formed of polypropylene or polyethylene. In oneconfiguration, the exoskeleton 1024 is formed of high densitypolyethylene. The high density polyethylene provides an improved flexurefor the mask assembly when compared to more rigid materials, such aspolypropylene or polycarbonate.

The exoskeleton 1024 provides some reinforcement to the ballooning maskseal 1020 while remaining supple enough to provide a desired level offlexure in the mask assembly 1012. Desirably, the overlap of theexoskeleton 1024 and the mask seal 1020 helps to provide a desiredsealing over the bridge of the nose of the wearer and down the sides ofthe face in the vicinity of the tear ducts of the wearer.

With reference to FIG. 41, the exoskeleton 1024 preferably comprises anopening 1060 defined by a rim 1062. The opening 1060 preferably isgenerally ovular in shape, similar to the opening 1042 defined withinthe mask seal 102. Preferably, the rim 1062 is generally flattened offrelative to the curvilinear appearance of the exoskeleton. In otherwords, the rim 1062 defines a substantially planar surface not unlike aplateau on the otherwise curvilinear exoskeleton 1024. Moreparticularly, as shown in FIG. 42, in the illustrated configuration, thecurve of the rim 1062 in side view results in a lower portion 1061 thatis generally parallel with a forward facing surface of the endoskeleton1022 and an upper portion 1063 that is generally normal to that samesurface. Preferably, the side surfaces of the rim also are generallyparallel with the forward facing surface of the endoskeleton 1022. Insome configurations, all but one portion of the rim is generallyparallel to the surface of the endoskeleton.

The exoskeleton 1024 comprises an outer surface 1064. The outer surface1064 preferably comprises a plurality of mounting members 1066. Themounting members 1066 can be secured to the exoskeleton 1024 in anysuitable manner. In the illustrated configuration, the mounting members1066 are integrally molded with the exoskeleton.

The illustrated exoskeleton 1024 comprises four mounting members 1066.As shown in FIG. 42, the illustrated mounting members 1066 preferablyextend substantially horizontally from the illustrated mask assembly1012 when the mask assembly 1012 is viewed in side view. As also shownin FIG. 39, the mounting members 1066 also preferably extendsubstantially parallel to the generally vertical center or medial planeV. In some configurations, the mounting members 1066 extend generallyparallel with a tensile force that will be applied by the headgearassembly 1014.

With reference to FIG. 39, a first generally horizontal plane P1 and asecond generally horizontal plane P2 are illustrated with dashed lines.Preferably, the position of the two planes P1, P2 are generally bisectedby a plane of force, such as that shown in FIG. 26. When viewed from thefront, as shown in FIG. 39, a first area A1 is defined higher than thefirst generally horizontal plane P1 and a second area A2 is definedlower than the second generally horizontal plane P2. Preferably, thefirst area A1 is the same as the second area A2. In addition, the topmounting members 1066 preferably are positioned sufficiently low todecrease the likelihood of the straps from encroaching into the eyeregion of the wearer. In some configurations, the mounting members 1066are positioned sufficiently laterally outward from the vertical centerplane V that the straps will not cross when joined to the mask. In someconfigurations, the mounting member 1066 is positioned close to theoutermost edge of the exoskeleton 1024.

The mounting members 1066 can have any suitable shape. In theillustrated configuration, the mounting members 1066 generally tapersuch that they narrow in a direction away from the outer surface 1064.In other words, one or more of the mounting members 1066 can be taperingpins. Such a configuration aids in the coupling of the headgear assembly1014 to the mask assembly 1012. In some configurations, the mountingmembers 1066 can be generally cylindrical. In a preferred configuration,the mounting members do not comprise an enlarged head portion. Anenlarged head portion can increase a pressure exerted against a wearer'sface during fitting of the interface assembly. Accordingly, an enlargedhead portion, while useable, is less desirable.

Endoskeleton

The mask assembly 1012 also comprises the endoskeleton 1022. Theendoskeleton can be formed of any suitable material. Preferably,however, the endoskeleton 1022 is formed of polypropylene. Desirably, atleast a central portion of the endoskeleton 1022 is substantially rigid.

The illustrated endoskeleton 1022 is generally encircled by theexoskeleton 1024 but at least a portion of the endoskeleton 1022 extendsthrough the exoskeleton 1024. In the illustrated configuration, acentral portion 1070 of the endoskeleton 1022 extends through theopening 1060 in the exoskeleton 1024. More preferably, the centralportion 1070 of the endoskeleton 1022 extends through the opening 1060of the exoskeleton 1024 as well as the opening 1042 of the mask seal1020. In some configurations, the central portion 1070 has an increasedwall thickness to provide increased rigidity to the central portion 1070relative to the surrounding portions of the endoskeleton 1022.

The illustrated central portion 1070 comprises a generally rectangularor ovular configuration. Preferably, the central portion 1070 is sizedand configured to extend into and/or through at least one of the opening1042 of the mask seal 1020 and the opening 1060 of the exoskeleton 1024.

With reference now to FIG. 43 and FIG. 44, an undercut 1076 that definesa groove 1072 preferably surrounds or substantially surrounds thecentral portion 1070. A shoulder 1074 can be defined along at least partof the central portion 1070 by the groove 1072. While the illustratedgroove 1072 generally encircles the central portion 1070 and creates asingle shoulder 1074 that encircles the central portion 1070, multipledistinct grooves 1072 and/or shoulders 1074 can be used to set apart afirst portion of the endoskeleton 1024 from a second portion of theendoskeleton 1024.

The undercut 1076 preferably varies about the periphery of the centralportion 1070. In other words, in the illustrated configuration, theundercut 1076 is more pronounced at the bottom and along the sides ofthe illustrated configuration relative to the top. For example, butwithout limitation, the undercut 1076 can be about 2 mm to about 3 mm atthe bottom and about 0 mm at the top of the central portion 1070. Insome configurations, the undercut can extend fully around the periphery,which would result in a configuration that is more difficult to assembleonce assembled. Where the undercut extends fully around the periphery,the undercut sizing can vary among differing regions. Changing theundercut sizing can vary the force required to assemble the product aswall as the force required to disassemble the product.

Preferably, the undercut 1076 facilitates a snap fit between theendoskeleton and the rim 1062 that defines the opening 1060 in theexoskeleton. Thus, the endoskeleton and the exoskeleton preferably snaptogether. For example, the bottom portion of the rim 1062 can be slippedunder the shoulder 1074 into the region defined by the undercut 1076.The exoskeleton 1024 then is forced against the endoskeleton 1022 suchthat the remainder of the rim 1062 slides over the shoulder 1074 intothe region defined by the undercut 1076, which results in the rim 1062snapping into position over the shoulder 1074.

With reference to FIG. 44, the rim 1062 of the exoskeleton 1024preferably has a length XL, a width XW and a perimetric length XP. Theseexoskeleton dimensions are defined in the illustrated configurationalong the innermost portion of the rim 1062. The shoulder 1074 of theendoskeleton 1022 also has a length NL, a width NW and a perimetriclength NP. A perimetric length is the encircling length in theillustrated configuration. For example, if the rim were a perfectcircle, then the perimetric length would be the circumference. In theillustrated configuration, the difference between the endoskeletonlength and the exoskeleton length is less than the difference betweenthe endoskeleton width and the exoskeleton width (i.e., NL−XL<NW−XW). Inaddition, in the illustrated configuration, the exoskeleton perimetriclength XP is less than the endoskeleton perimetric length NP. Theserelationships help to create the snap fit between the endoskeleton 1022and the exoskeleton 1024.

In the illustrated configuration, the flange 1044 that defines theopening 1042 in the mask seal 1020 is positioned in or along the groove1072 such that the flange 1044 can be tightly sandwiched between theendoskeleton 1022 and the exoskeleton 1024. By tightly sandwiching themask seal 1020 between the endoskeleton 1022 and the exoskeleton 1024,leaks from within the mask seal 1020 can be reduced or eliminated. Inaddition, the mask seal 1020 then is secured between the forward surfaceof the endoskeleton and the rearward surface of the exoskeleton. Theendoskeleton can underlie substantially the same portions of the maskseal 1020 that the exoskeleton overlies.

With continued reference to FIG. 43 and FIG. 44, the endoskeleton 1022provides a region in which a valve opening 1080 and a breathingconnection opening 1082 can be positioned. More particularly, thecentral portion 1070 of the endoskeleton 1022 accommodates the openings1080, 1082. Because the endoskeleton provides the openings 1080, 1082,one or both of the exoskeleton 1024 and the mask seal 1020 preferably donot overlie at least this portion of the endoskeleton.

The valve opening 1080 preferably accommodates an antiasphyxiation valve1084. In the illustrated configuration, at least one and preferably twostruts 1086 extend into the opening 1080. The struts 1086 connect to amounting member 1088. The mounting member 1088 receives the valve 1084,which preferably comprises a single piece construction including abarbed stem that is locked within the mounting member 1088 when properlyinserted. In the illustrated configuration, the mounting member 1088 isring-like. Other techniques for mounting an antiasphyxiation valve 1084also can be used.

With reference to FIG. 40, a breathing tube connector 1090 is shownremoved from the rest of the mask assembly 1012. The illustratedbreathing tube connector 1090 comprises a stem portion 1092 and a ballportion 1094. The ball portion 1094 is received within a socket 1096defined within the opening 1082. In particular, in the illustratedconfiguration, the stem portion 1092 can be inserted through the opening1082 until the ball portion 1094 snaps into place within the socket1096. Such a configuration allows swiveling and pivoting of the stemportion 1094 relative to the endoskeleton 1022.

The illustrated breathing tube connector has an inlet end 1100 and anoutlet end 1102. The outlet end 1102 preferably has a larger hydraulicdiameter compared to the inlet end 1100. By providing an outlet end 1102with a hydraulic diameter that is larger than the inlet end 1100, theflow of gases or fluids through the connector 1090 slows from the inletend 1100 to the outlet end 1102.

Headgear Assembly

With reference again to FIG. 37, the headgear assembly 1014 comprises aframe 1110, a first set of relatively axially inelastic straps 1112, afirst set of relatively axially elastic straps 1114 and a second set ofrelatively axially inelastic straps 1116. As explained above, the firstset of relatively axially elastic straps 1114 preferably are secured tothe frame 1110 and the mask assembly 1012 such that a coarse fitting ofthe interface assembly 1010 to the wearer can be accomplished veryrapidly. In other words, the relatively axially elastic straps 1114,which extend between the frame 1110 and the mask assembly 1112, stretchto enable initially positioning and coarse fitting of the mask and theelastic straps 1114 also help maintain the position of the mask assembly1112 during final fitting. The first and second sets of relativelyaxially inelastic straps 1112, 1116 then can be used to achieve asuitable final tension level for the interface assembly.

With reference now to FIG. 45, the illustrated frame 1110 is shown priorto being configured for donning. The frame 1110 preferably is semi-rigidsuch that it is sufficiently stiff to, when assembled, assume athree-dimensional shape with dimensions approximating the head of thewearer for whom the frame is designed to fit while remainingsufficiently flexible to generally conform to the anatomy of the wearer.In some configurations, the frame 1110 is formed from polyethylene orthermoplastic rubbers. In some configurations, the frame can have one ormore surfaces that is surface textured in the manner described abovewith respect to the seal member.

The illustrated frame 1110 comprises a first upper arm portion 1120, asecond upper arm portion 1122, a first top strap portion 1124 and asecond top strap portion 1126. Preferably, the first upper arm portion1120 and the second upper arm portion connect together. More preferably,the first upper arm portion 1120 and the second upper arm portion 1122connect together in a region that would be positioned at the back of thehead of the wearer. The first and second upper arm portions areconfigured to wrap forward and upward from a location proximate theoccipital protuberance of the wear to a location above the ears of thewearer. In the illustrated configuration, the first and second upper armportions 1120, 1122 are integrally formed. In some configurations,however, the first and second arm portions 1120, 1122 can be separatelyformed and connected together.

Each of an end of the first upper arm 1120 and an end of the secondupper arm 1122 comprises a post 1130. The posts 1130 preferably comprisea generally flat head 1132 and a central aperture 1134. Otherconfigurations also can be used, as desired.

With reference to FIG. 37, the first top strap portion 1124 and thesecond top strap portion 1126 extend from the first and second upperarms 1120, 1122 respectively. Preferably, the first and second top strapportions 1124, 1126 are configured to connect together and, when soconnected, to extend over the top of the head of the wearer. In theillustrated configuration, the first top strap portion 1124 comprises aseries of holes 1140 while the second top strap portion 1126 comprises abuckle 1142 and one or more posts 1144. The end of the first top strapportion 1124 can be passed through the buckle 1142 and the posts can beinserted into corresponding holes 1140 to secure the top strap portions1124, 1126 together.

As described above, the frame 1110 can be connected to the mask assembly1012 with the first and second inelastic straps, 1112, 1116 and theelastic straps 1114. In one configuration, the elastic straps 1114 andthe first inelastic straps 1112 have a portion that is secured together.The straps can be secured together in any suitable manner. For example,the straps can be mechanically fastened (e.g., hook and loop fasteners,hole and post or snap fit) or welded. Securing the straps 1112, 1114serves to limit the movement of the first inelastic strap 1112 duringfitting such that the first inelastic strap 1112 is less likely to flopinto the face of the wearer. The secured portion of the straps 1112,1114 preferably is secured to the frame 1110 at the posts 1130. Bymounting the secured portion to the posts 1130, if the secured portionseparates, both of the straps 1112, 1114 will remain connected to theposts 1130. In addition, the straps 1112, 1114 are pivotable relative tothe posts 1130 and/or the frame 1110.

The second inelastic straps 1116 preferably are formed of a singlemonolithic piece. The inelastic straps 1116 are configured to wrap frombehind the head of the wearer to the mask assembly 1012. Preferably, thesecond inelastic straps 1116 extend at a location generally below theears of the wearer to the mask assembly 1012. The second inelasticstraps 1116 can be secured to the frame 1110 in any suitable manner. Insome configurations, the second inelastic straps 1116 can thread througha portion of the frame 1110. In other configurations, the secondinelastic straps 1116 can be ultrasonically welded to a portion of theframe 1110.

Preferably, the second inelastic straps 1116 underlie at least a portionof the frame 1110. In the illustrated configuration, an enlarged portion1150 at the juncture between the second inelastic straps 1116 and theframe 1110. The enlarged portion 1150 can include an upper tab 1152 anda lower tab 1154. In some configurations, the upper tab 1152 is largerthan the lower tab 1154. The upper tab 1152 advantageously provides afinger gripping surface that can be used to pull the frame into positionon the head of the wearer and that can be used to pull the frame off ofthe head of the wearer. One or both of the tabs 1152, 1154 also areconfigured to wrap over the edges of the frame 1110 such that the edgesof the frame 1110 are protected from contacting the skin of the wearerdirectly.

The elastic straps 1114, as described above, can be connected to theframe 1110 and the mask assembly 1012. In some configurations, theelastic straps 1114 are adhered, cohered, molded, welded or otherwisepermanently affixed to the mask assembly 1012. In one configuration, theelastic straps 1114 are secured to the exoskeleton proximate an upperset of the mounting member 1066.

The upper and lower inelastic straps 1112, 1116 preferably include aseries of openings or the like 1160. The openings 1160 can be holes orcan be crossed perforations or the like. The openings 1160 receive themounting members 1066 and provide for differing levels of load appliedbetween the mask seal 1020 and the face of the wearer. Preferably, thearea of the inelastic straps 1112, 1116 surrounding the series ofopenings or the like 1160 can be embossed under heat to define areinforced region 1170. By embossing the material, the openings 1160 orthe like can be reinforced. Other suitable techniques also can be usedto reinforce the openings. For example, eyelets, plastic reinforcements,thicker materials, or the like also can be used.

With reference to FIG. 46, when the lower inelastic straps 1116 aresecured to the mounting members 1066, the lower inelastic straps 1116preferably form an angle α less than 90 degrees with an inner face 1172of the respective mounting member 1066. Similarly, as shown in FIG. 46,when the upper inelastic straps 1112 are secured to the mounting members1066, the upper inelastic straps 1112 preferably form an angle β lessthan 90 degrees with an inner face 1174 of the respective mountingmember 1066.

As with other configurations described above, the illustrated straps1112, 1116 tend to present forward naturally due to the semi-rigidconfigurations. In some configurations, only a portion of theillustrated straps 1112, 1116 are formed of a semi-rigid construction.The portion can provide sufficient lateral or forward presentation tokeep the straps from being hidden or tangled behind the head of thepatient.

Preferably, the straps 1112, 1116 are flexible enough to conform to thegeometry of the head while still being stiff or rigid enough to presentforward. In some configurations, the straps 1112, 1116 are formed of alaminated nonwoven polypropylene construction. Preferably, the laminatednonwoven polypropylene construction comprises stiff laminations that aresandwiched between soft nonwoven polypropelene. In some configurations,nonwoven polyethylene terephthalate or nonwoven polyethylene could beused instead of soft nonwoven polypropelene. In one configuration, thelaminated construction comprises four laminated sheets: 2 outer sheetsare 70 gsm PE/PET bicom and 2 inner sheets are 100 gsm nonwoven PPE.

The forward presenting nature of the straps 1112, 1116 makes positioningand alignment of the apertures 1160 with the attachment posts 1066 ofthe interface body intuitive and easy. Moreover, the forward presentingstraps allows adjustment of the fit of the interface assembly to beadjusted on the front of the mask.

With reference now to FIG. 47, another configuration is shown in whichan antiasphyxiation valve 2084 is captured within a passage 2085 definedwithin an endoskeleton 2022. Preferably, an insert 2087 encloses atleast a portion of the passage 2085 such that the valve 2084 is capturedwithin the passage 2085 between the insert 2087 and at least one strut2086. While the term insert has been used, the component need not beinserted into the passage and can simply overly or otherwise cover theassociated end of the passage such that the valve 2084 is secured intothe passage from the outside. In the illustrated configuration, twostruts 2086 join at a mounting member 2088 and the struts 2086 andmounting member 2088 collectively span the passage 2085. In someconfigurations, the mask comprises a construction in which the valve2084 is sandwiched between an insert (e.g., the insert 2087) and aportion of the mask body (e.g., the two struts 2086).

As shown in FIG. 50, the two struts 2086 preferably arc rearward from awall 2091 that defines the passage 2085. The arc in the struts 2086moves the valve 2084 closer to the face of the user, which helps toreduce the internal volume of air contained within the mask. Moreover,such a configuration helps to provide a lower profile configuration. Insome configurations, the portion of the mask body that forms a part ofthe sandwich around the valve is integrally formed with the mask body.Preferably, the struts 2086 are integrally formed with the surroundingportion of the mask body (e.g., the endoskeleton 2022). In other words,preferably, the struts 2086 are a monolithic structure with at least aportion of the mask body. More preferably, the struts 2086 are amonolithic structure with the endoskeleton 2022.

The insert 2087 comprises an outer surface 2101 that is received withinthe wall 2091 that defines the passage 2085. Preferably, the outersurface 2101 comprises a surface 2103 that engages with a recess 2105that encircles the illustrated passage 2085 and that is formed at a baseof the struts 2086. The recess 2105 and the surface 2103 lock the insert2087 into position within the endoskeleton 2022. Any other suitabletechnique for securing the insert 2087 to the endoskeleton 2022 can beused.

The illustrated insert 2087 also comprises an aperture 2107 thatreceives a post 2109 of the valve 2084. Preferably, the post 2109 has abarbed configuration such that the post 2109 can be substantiallysecured to the insert 2087. Any other suitable manners of securing thevalve 2084 to the insert 2087 also can be used. In some configurations,the valve 2084 can be secured to the mask body (e.g., struts 2086 orother portion of the endoskeleton 2022). In other words, while the valve2084 is mounted to the insert 2087 and seated on the insert 2087, thevalve can be mounted to the mask body (e.g., a portion of theendoskeleton 2022) and still seat on the insert 2087, the valve can bemounted to the mask body and be seated on the mask body or the valve canbe mounted to the insert and seated to the mask body. In other words,the valve 2084 can be mounted to either the mask body or the insert andthe valve 2084 can seat against either the mask body or the insert.Preferably, the valve 2084 can be secured to the insert 2087 prior tothe insert being secured to the mask body. More preferably, the valve2084 can be secured to the insert 2087 prior to the insert being securedto the endoskeleton 2022. Even more preferably, the valve 2084 can besecured to the insert 2087 prior to the insert being secured to asubstantially rigid or substantially inflexible portion of theendoskeleton 2022. By mounting the insert 2087 to a substantially rigidor substantially inflexible portion of the mask body (e.g., the centralportion of the endoskeleton 2022), the insert 2087 can be more securedconnected to the mask body.

The illustrated valve 2084 also comprises a recess 2111. The recess 2111receives at least a portion of a centering boss 2113 formed on themounting member 2088. The cooperation of the recess 2111 and thecentering boss 2113 maintain the valve 2084 in a central location withinthe passageway 2085 when the valve 2084 is secured between the insert2087 and the struts 2086 and mounting member 2088.

Moreover, the illustrated insert comprises an end recess 2115 thataccommodates an outer lip 2117 of the valve 2084. In addition, steps2119 are formed at the base of the struts 2086. The steps 2119 limit thedepth to which the insert 2087 can be inserted into the passage 2085 andcan bear against the end of the insert 2087 such that the surface 2103of the insert 2087 is urged back against the recess 2103.

As shown in FIG. 47, the insert 2087 also comprises a passage 2121through which air can flow when allowed by the valve 2084. Theillustrated passage 2121 is generally annular. In some configurations,the passage 2121 can be defined by one or more openings. Any othersuitable passage can be defined between the valve and the atmosphere.

Advantageously, the illustrated valve 2084 is captured within theendoskeleton 2022 with the insert 2087. Accordingly, the valve 2084 isless likely to separate from the endoskeleton 2022 during use. In someconfigurations, the valve 2084 can be mounted in the exoskeleton, acombination of the endoskeleton 2022 and the exoskeleton or anothercomponent of the interface. Preferably, the insert 2087 is either flushwith and recessed within the surrounding portion of the mask body suchthat removal of the insert 2087 from the mask body is difficult if notimpossible. More preferably, the insert 2087 does not comprise asignificant protruding surface such that purchase on the insert 2087 forpurposes of removing the insert is rendered difficult if not impossible.

The foregoing description of the invention includes preferred formsthereof. Modifications may be made thereto without departing from thescope of the invention as provisionally indicated by the accompanyingclaims. In particular, it will be appreciated that the present inventiondescribes a number of patient interface inventions (masks) as well as anumber of headgear inventions and adjustment systems. While thespecification gives a number of examples in which various interfaceembodiments are combined with various headgear embodiments, each andevery possibility of the inventions are not explicitly given. It isintended that each and every combination of elements may be utilizedalone or in combination as part of the present invention. Similarly,other known headgear and interface designs may also be used with theinterface and headgear designs of the present invention respectively.

What is claimed is:
 1. An interface assembly comprising a mask assembly,the mask assembly comprising an endoskeleton, the endoskeletoncomprising a central portion, the central portion being delimited by agroove that defines a shoulder, a seal member overlying at least aportion of the endoskeleton, the seal member comprising an opening, atleast part of the central portion of the endoskeleton being exposedforwardly through the opening in the seal member, an exoskeletonoverlying at least a portion of the seal member, the exoskeletoncomprising a rim that defines an opening, the rim and the shoulderinterlocking to secure the endoskeleton to the exoskeleton with the sealmember secured between the endoskeleton and the exoskeleton, at leastpart of the central portion of the endoskeleton being exposed forwardlythrough the opening in the exoskeleton.
 2. The interface assembly ofclaim 1, wherein the central portion of the endoskeleton comprises anopening, a breathing tube connector being secured to the opening in thecentral portion of the endoskeleton.
 3. The interface assembly of claim1, wherein the central portion of the endoskeleton comprises an opening,an antiasphyxiation valve being secured to the opening in the centralportion of the endoskeleton.
 4. The interface assembly of claim 1,wherein the central portion of the endoskeleton comprises a firstopening and a second opening, a breathing tube connector being securedto the first opening and an antiasphyxiation valve being secured to thesecond opening.
 5. The interface assembly of claim 1, wherein the sealmember comprises a face contacting flange that is configured togenerally encircle a mouth opening and nasal openings of a wearer. 6.The interface assembly of claim 1, wherein the exoskeleton is configuredto enclose at least a tip of a nose of a wearer.
 7. The interfaceassembly of claim 1, wherein an upper portion of the mask assembly isgenerally triangular and a lower portion of the mask assembly isgenerally U-shaped.
 8. The interface assembly of claim 7, wherein themask assembly has a longer dimension from top to bottom than from sideto side.
 9. The interface assembly of claim 1, wherein the mask assemblyis more flexible about a generally vertical center plane than anygenerally horizontally extending plane.
 10. The interface assembly ofclaim 1, wherein the seal member comprises a flange that borders theopening of the seal member, the flange of the seal member beingpositioned within the groove of the endoskeleton and being securedwithin the groove by the interlocking endoskeleton and exoskeleton. 11.The interface assembly of claim 1, wherein a plurality of mountingmembers are secured to the exoskeleton.
 12. The interface assembly ofclaim 11, wherein at least one of the plurality of mounting memberscomprises a tapering pin.
 13. The interface assembly of claim 12,wherein the tapering pin extends generally parallel to a substantiallyvertical medial plane.